This blog will explore the world of automotive diagnostics. We will show a new case study every week.I will also offer my opinions on various issues in the automotive world.
Sunday, December 29, 2013
2000 Jeep Grand Cherokee
Here is a 2000 Jeep Grand Cherokee 111,087 miles with a 4.7 liter engine. This is actually at a transmission shop that got it from another shop. The vehicle sets a P1768 code for transmission control relay always off and the transmission goes into failsafe. The previous shop has tried a Transmission Control Module, Transmission Control relay, and a transmission solenoid pack. These vehicles are very common in my area and they have various issues. Lets look at the code and code set criteria.
Ok, so we have some code set and quite the number of possibilities. One item that is not listed is an issue with the solenoid pack or wiring. I have seen wiring down to the solenoid pack be frayed or shorted to power, ground, or another wire and set this code. Probably, what the other shop was thinking when they tried a solenoid pack. Lets look at the circuits involved for the Transmission Control relay.
So we have a regular 4 wire relay setup. Fused battery power comes into terminal #30 and when the relay is energized it flows out on terminal #87 to the TCM (watchdog circuit) and to the transmission solenoids. Remember this is a 4.7 liter. The control side of the relay is a constant ground from G104 to terminal #85 and the TCM powers terminal #86 to activate the relay. I put that in bold because most relay control circuits are ground activated. This is just the opposite. When the TCM wants to failsafe the transmission it discontinues the power to the relay and power is cut to the transmission solenoids and the transmission defaults to whatever failsafe gear it is engineered for. So how should I proceed? Remember, I have to work fast and efficiently. I need to know is the TCM turning off the relay? Is the relay really turning off? Are there other factors involved? I decide I am going to scope the relay output, relay control, and the relay ground for starters.
If you look on the diagram everything I want to see goes through two connectors C102 and C103. I am always very suspicious of Chrysler connectors and connectors in general. I don't like to just start disconnecting and inspecting connectors visually. The simple action of disconnecting and reconnecting can temporarily or permanently solve an issue. I backprobe whenever possible. Lets setup.
Here are the components labeled out. This is the right rear of engine compartment. Again, I am using Pomona backprobes available from Aeswave. They provide me with great confidence in testing with being minimally invasive. Let's go for a ride. I don't even get out of the driveway of the shop and the code sets and the transmission goes into failsafe. Lets look at the scope data.
Now I can get a picture of what is going on. The first thing I notice is my ground to the relay is flipping out. The next is the TCM is not commanding the relay off. The relay output is dropping out. Lets zoom in on that moment.
There it is the ground is being lost and then the relay output is being lost. Look at my scaling for channel 3 (blue). A good ground in this type of circuit maybe 200mv at the most. I clear the code and repeat this a couple of times always with the same result. We are losing the ground. Lets go find this bad ground.
Why does this always happen to me? It seems like every time I need to find a ground or a connector it is a N/S. A no show or a not shown. Ok, we know it is right rear of engine. I follow the harness and it disappears down the back of the motor. It is tight. My guess it is attached to the bellhousing or back of the cylinder head. These vehicles get transmissions, cylinder heads, motor swaps, etc. So what can I do to make sure this will fix this elusive problem?
I run a jumper wire from battery negative to the wire that is supposed to be grounded by G104. I clear codes and road test. I left my scope attached and recorded.
Looks good to me. The transmission performed well. I figured I would also see how it is on the scanner as well.
Looking good. Switched battery and ignition feed voltages are right where they should be. No codes and like I said transmission performs well. I inform the transmission shop owner of my findings. I give him his options on repairing this vehicle. At this point the vehicle harness should be closely inspected and repaired/replaced.
Sunday, December 1, 2013
Scantools.....
If there is one question I get asked frequently by shop owners, technicians, and emails alike is-What scantool should I get? Or, Is this scantool good? Or, I just spent $12k on this scantool and it doesn't do this procedure on this vehicle.
I typically will follow this up with questions of my own. Such as. What manufacturer is the bulk of your work? What functions do you want to do with the scantool? What is your budget?
Without knowing the answers to those questions it is awfully hard to give sound advice. I see many shops that use a $10k scantool like a $99.00 code reader. They would have been better served spending the $9K someplace else in my opinion. Like maybe some training. If that works for you and your shop so be it.
In this age of automotive diagnostics it is nearly impossible to be "loaded for bear" on every manufacturer. Unless, you have deep pockets. Even with that are you using all the capabilities of all your tooling? Lots of aftermarket companies make boastful claims when it comes to coverage and capabilities. Unfortunately, when the tool is in your hand and need to do a function they can fall short at the worst of times. I often say that a good aftermarket tool will have 85% capability on 85% of the vehicle lines. However, that 15% can kill you.
Here is a small example of aftermarket tooling. Any one of these are a very capable scantool. Being able to read codes/erase, view scan data, graph, and perform bi directional functions on different modules. Some do it better than others. Some are strong on this manufacturer but weaker on others. Again the 85%/85% rule. Some, I have been impressed with and others well not so much. Sometimes it is just easier to break out an aftermarket handheld tool rather than hook up a OE laptop based tool to check data or codes. Time is money. Some aftermarket tools actually graph better/faster than the OE tool for certain manufacturers.
Here are some OE scantools. These are manufacturer specific tools. Some are handheld and some are PC/Laptop based. The world of OE tooling is a convulated and confusing world. These tools walk the walk. With these tools you should be able to have 100% capability for that manufacturer. Notice, how I said should. They have their hiccups as well. It happens from time to time. Not often though. If you want to do a procedure from start to finish and want to be sure you can do it then OE tooling is for you.
One thing to point out in this photo is the GM Tech2. There is been much chatter about the demise of this tool. Well, it had a recent update and I used it to finish up an ABS control module setup on a 2013 Cadillac CTS just the other day. Granted, there is a PC based version of Tech2 called Tech2Win that could have done the same procedure.
Here is a screen shot from Tech2Win. I still prefer the handheld to the PC based. The point here is don't get rid of your Tech2 and if you do service a lot of GM vehicles a Tech2 is still a smart tooling investment.
You have to ask yourself those three question I posted earlier when choosing scantools. Some tool companies/vendors allow for a "test drive" of tooling. That is always a smart idea take advantage of if possible. Nothing worse than investing money in a tool that disappoints. A test drive of a week should let you know if that tool is right for you and your shop. Beware, of any tool company that claims that you will never need another scantool.
Another point to remember is comfort. A tool that everyone is intimidated to use will be a tool that sits in your toolbox making you no money. There are plenty of techs throughout the country that are diagnosing issues with vehicles with tooling that many would scoff at. It works for them and they are using that tool to its potential. Many times it is not the tool but the tool wielder. The general publics perception that all you do is plug into the vehicle and the scantool "tells" you what part is bad is grossly exaggerated. The best scantool you have is your brain. Technicians fix vehicles not scantools. Remember that always.
I typically will follow this up with questions of my own. Such as. What manufacturer is the bulk of your work? What functions do you want to do with the scantool? What is your budget?
Without knowing the answers to those questions it is awfully hard to give sound advice. I see many shops that use a $10k scantool like a $99.00 code reader. They would have been better served spending the $9K someplace else in my opinion. Like maybe some training. If that works for you and your shop so be it.
In this age of automotive diagnostics it is nearly impossible to be "loaded for bear" on every manufacturer. Unless, you have deep pockets. Even with that are you using all the capabilities of all your tooling? Lots of aftermarket companies make boastful claims when it comes to coverage and capabilities. Unfortunately, when the tool is in your hand and need to do a function they can fall short at the worst of times. I often say that a good aftermarket tool will have 85% capability on 85% of the vehicle lines. However, that 15% can kill you.
One thing to point out in this photo is the GM Tech2. There is been much chatter about the demise of this tool. Well, it had a recent update and I used it to finish up an ABS control module setup on a 2013 Cadillac CTS just the other day. Granted, there is a PC based version of Tech2 called Tech2Win that could have done the same procedure.
You have to ask yourself those three question I posted earlier when choosing scantools. Some tool companies/vendors allow for a "test drive" of tooling. That is always a smart idea take advantage of if possible. Nothing worse than investing money in a tool that disappoints. A test drive of a week should let you know if that tool is right for you and your shop. Beware, of any tool company that claims that you will never need another scantool.
Another point to remember is comfort. A tool that everyone is intimidated to use will be a tool that sits in your toolbox making you no money. There are plenty of techs throughout the country that are diagnosing issues with vehicles with tooling that many would scoff at. It works for them and they are using that tool to its potential. Many times it is not the tool but the tool wielder. The general publics perception that all you do is plug into the vehicle and the scantool "tells" you what part is bad is grossly exaggerated. The best scantool you have is your brain. Technicians fix vehicles not scantools. Remember that always.
Thursday, November 28, 2013
Timing is everything
Here we have a 2005 GMC Envoy 4.2 Liter engine. The vehicle is fairly clean and has 112,361 miles on it. The complaint is the MIL Lamp is on and is setting a P0017 code. This code indicates an issue between Crankshaft and Camshaft correlation. The truck runs well and the shop owner was hoping there was a reprogramming that would solve this. A quick check of present calibration and available updated calibrations yielded nothing for this code. Time to roll up the sleeves. First step is to look at the code and more importantly code set criteria. While we are at it check for pertinent TSB's.
Here is the code P0017. I love the code set criteria. A calibrated amount. What is a calibrated amount? Time to dig a bit. I look for TSB's and PI's on the OE site.
I come up with this document. A world of information including the specified calibrated amount as well as a wealth of causes for this code. A little background on these engines. They utilize a camshaft actuator or phaser on the front of the exhaust camshaft that is loaded to a neutral/base position. When the PCM wants to actuate this actuator it duty cycles an oil control solenoid that will in turn feed oil to the actuator and in this case will retard the exhaust camshaft. Basically, this operation takes the place of EGR operation and it also improves overall efficiency. Like all engines that utilize this type of design it is very reliant upon proper oil level, viscosity, and pressure.
Here is the front view of the engine. The oil control solenoid is in the head right by the power steering pump. The camshaft sensor is also on the front of the cylinder head right by the upper radiator hose.
Here is a close up of the oil control solenoid. I see plenty of issues with these. They clog up, the portion inside the head gets clogged up and doesn't allow the oil solenoid to do its job properly. Typically, when this happens the vehicle runs really poor at an idle but runs decent raced up. Think of a vehicle with a stuck open EGR valve. This vehicle runs rather well at an idle. Scantool data is only going to give me a small portion of what I need to know. My play is to scope crank and cam sensors.
Well here is Crank sensor on channel 1 in yellow and Cam sensor on channel 2 in Green. Is it good? Is it bad? I don't know. This is where it is nice to have a known good. It just so happens that there is another similar vehicle on the lot. This vehicle is running fine and is just in for servicing. Lets take a look at that one and see if we can see any differences.
Just a little math here as well. One crankshaft rotation (from signature to signature) took approximately 100ms. That would mean 3.6 degrees per 1ms. The code set was 16.31 degrees which is approximately 4.5ms. Looking at the bad pattern it is real close to being about 4.5ms out. If memory serves me these cam sprockets have 48 teeth that would yield 15 degrees per tooth. So a tooth out with a little stretch is a possibility here as well.
Tuesday, November 12, 2013
Details, Details, Details......
In the automotive diagnostic world details are everything. Missing a vital piece of scan data can lead to a misdiagnosis or missing a step during a programming event can cause issues. You have to pay attention at all times. It is something I strive for. To be a detail orientated person and that translates to my business as well.
A shop owner called me one day frantic about a 1999 Ford F150 pickup truck with 78,820 miles that he could not get rid of a P0401 EGR code. I arrived at the shop to see a very clean low mileage Ford truck with a 4.6 liter. Lifting up the hood I could see a new EGR valve, a new EVR (EGR solenoid), a new DPFE (Delta pressure feedback egr) sensor, a new exhaust tube for the EGR, and new DPFE hoses. Some parts the shop put on and others the customer installed. I quickly ran a KOEO (Key on engine off) test there was a P0401 (EGR low flow) code in KAM. No on demand codes. I moved on to the KOER (Key on engine running) test but first I hooked up an old fashioned vacuum gauge on the vacuum hose between the EVR and EGR valve. When you run a KOER test the PCM will activate certain outputs such as EGR and look for change. I was interested in if there was any vacuum going to the EGR valve during the test. During the test I indeed saw vacuum going to the EGR valve. The control side of the EGR system seemed to be in order. The test completed and a P0401 was set in KOER. Next step was to actually put vacuum to the EGR valve at an idle and see if it caused the engine to run rough indicating the EGR was opening and that the exhaust and intake passages for EGR were not clogged. Putting vacuum to the EGR valve didn't cause the engine to change at all. I could physically see the EGR valve diaphragm opening. I unbolted the EGR valve and started the motor the intake port were completely clogged. No vacuum could be felt. Considering the low mileage and the common issues with this issue I instructed the shop to remove the throttle body so I could show him the clogged ports. 10 minutes later the throttle body was off and sure enough the ports were clogged solid. Leaving the shop I gave the shop owner a quick rundown of how the system works and how it tests itself to see if it fully functioning.
A couple of days later I get a call from the shop owner saying he gave the vehicle back to the customer and the MIL (Malfunction illumination lamp) came back on and it has a P0401 again! Huh? This was a slam dunk diagnosis. I asked the shop owner if he ran a KOEO/KOER tests before releasing it to the customer. His reply was "I scanned it". I also asked him if he put vacuum to the EGR valve did the motor run rough or stall? Again, I got a reply "I think so". I told the shop owner I would stop by later in the day. Those that know me already know that this vehicle would be gnawing at me all day until I got there. I take things very personal. Did he clean the passages completely? Did another issue crop up?
I arrive at the shop and first thing I do is apply vacuum to the EGR valve and the engine ran very rough almost to a stall. Well, he has the passages clean now. Now, lets retest to see if it still is getting vacuum to the EGR during a KOER test. It was. Ok, does the PCM actually know the EGR is opening and flowing. How the PCM knows this is from the DPFE sensor. It senses flow across a controlled orifice in the EGR tube via those two brand new hoses. I hooked up my scantool and graphed the DPFE voltage. On a plastic DPFE such as this one KOER with no EGR flow you should be at 1.00 volt as EGR flow increases so does the voltage. I normally can get upwards of close to 4.0 volts or more when adding vacuum to the EGR valve.
As you can see from the graph I started out at close to 1 volt. I then added vacuum, took it away and reapplied vacuum. But, my voltage went down. Way down to .14v. What is going on? I know the hoses at the DPFE are reversed. I reverse the hoses and redo my vacuum test.
A shop owner called me one day frantic about a 1999 Ford F150 pickup truck with 78,820 miles that he could not get rid of a P0401 EGR code. I arrived at the shop to see a very clean low mileage Ford truck with a 4.6 liter. Lifting up the hood I could see a new EGR valve, a new EVR (EGR solenoid), a new DPFE (Delta pressure feedback egr) sensor, a new exhaust tube for the EGR, and new DPFE hoses. Some parts the shop put on and others the customer installed. I quickly ran a KOEO (Key on engine off) test there was a P0401 (EGR low flow) code in KAM. No on demand codes. I moved on to the KOER (Key on engine running) test but first I hooked up an old fashioned vacuum gauge on the vacuum hose between the EVR and EGR valve. When you run a KOER test the PCM will activate certain outputs such as EGR and look for change. I was interested in if there was any vacuum going to the EGR valve during the test. During the test I indeed saw vacuum going to the EGR valve. The control side of the EGR system seemed to be in order. The test completed and a P0401 was set in KOER. Next step was to actually put vacuum to the EGR valve at an idle and see if it caused the engine to run rough indicating the EGR was opening and that the exhaust and intake passages for EGR were not clogged. Putting vacuum to the EGR valve didn't cause the engine to change at all. I could physically see the EGR valve diaphragm opening. I unbolted the EGR valve and started the motor the intake port were completely clogged. No vacuum could be felt. Considering the low mileage and the common issues with this issue I instructed the shop to remove the throttle body so I could show him the clogged ports. 10 minutes later the throttle body was off and sure enough the ports were clogged solid. Leaving the shop I gave the shop owner a quick rundown of how the system works and how it tests itself to see if it fully functioning.
A couple of days later I get a call from the shop owner saying he gave the vehicle back to the customer and the MIL (Malfunction illumination lamp) came back on and it has a P0401 again! Huh? This was a slam dunk diagnosis. I asked the shop owner if he ran a KOEO/KOER tests before releasing it to the customer. His reply was "I scanned it". I also asked him if he put vacuum to the EGR valve did the motor run rough or stall? Again, I got a reply "I think so". I told the shop owner I would stop by later in the day. Those that know me already know that this vehicle would be gnawing at me all day until I got there. I take things very personal. Did he clean the passages completely? Did another issue crop up?
I arrive at the shop and first thing I do is apply vacuum to the EGR valve and the engine ran very rough almost to a stall. Well, he has the passages clean now. Now, lets retest to see if it still is getting vacuum to the EGR during a KOER test. It was. Ok, does the PCM actually know the EGR is opening and flowing. How the PCM knows this is from the DPFE sensor. It senses flow across a controlled orifice in the EGR tube via those two brand new hoses. I hooked up my scantool and graphed the DPFE voltage. On a plastic DPFE such as this one KOER with no EGR flow you should be at 1.00 volt as EGR flow increases so does the voltage. I normally can get upwards of close to 4.0 volts or more when adding vacuum to the EGR valve.
Totally different story here.
We are flowing now. The DPFE hoses have a large and small opening and have to be orientated correctly at the EGR pipe and the DPFE. Somehow, someone managed to mix these up. You really have to try really hard to mix this up. Now, were these hoses like this on my first visit? I really can't say for sure. I didn't check-shame on me. I was so caught up on diagnosing the clogged passage I didn't see if the hoses were orientated correctly. To be honest this is the first time I have ever seen this. However, I won't be making this mistake ever again. I ran a KOER test and all was well.
Some details you don't see on the scantool. Some you have to see or feel.
Here is a 1999 Ford Expedition with a 5.4 liter. Shop has installed a new oxygen sensor for a P0135 (O2 heater circuit) code. New sensor and still same code. Now they are thinking it may have a bad PCM. I got called in and inspected the wiring. The connector for bank 1 sensor 1 is in an awful spot behind the passenger side of the engine. The clue that it may be a wiring issue is the newly installed remanufactured transmission. Bad things can happen to wiring when a transmission is installed especially to oxygen sensor wiring.
Well here it is the lock portion of one of the terminals for the heater circuit was broken. The terminal itself was also damaged. The terminal was being pushed out when the oxygen sensor was connected causing the heater circuit code.
Here is another one found with the eyes. Mitsubishi Montero with oxygen sensor codes. My first tipoff was the two different color connectors. Then a close inspection of the harness connector showed the locator tab was filed off. They used a left side sensor in the right side. They are all the same aren't they? Wire orientation was different. Very dangerous. Shop was lucky no PCM damage occurred.
A good technician not only uses his scantools, voltmeters, etc. He or she also utilizes sight, sound, smell, feel, etc. Pay attention to details and learn from your mistakes.
Sunday, November 3, 2013
Technician Training
This is a real sore subject with me. Almost every technician gripes about the lack of training in our industry. It is something I hear almost daily. I am often asked "When is the next training event?" I give information, hand out flyers, and even remind techs of upcoming training. Then why is it that I see the same familiar faces at every training event I attend? I will tell what I think.
It all comes down to sacrifice and commitment. If you want to become the best in whatever you do these two actions are paramount. When I ask the same people that were wondering about training why they weren't at a recent event. I get the usual excuses "I forgot", "It was on a Saturday and I couldn't swing it", "It was after work and I didn't feel like it", "It is too expensive". These aren't as bad as the people in this industry that think they don't need any training. They know it all, just ask them. I often say the minute you think you know everything in this industry you should walk over to your toolbox lock it up and look for another job. There is no one person in this industry that knows it all. You can always learn something. If you are not learning something everyday in this industry you are not paying attention.
Some training events are better than others. No doubt about that. However, I always pick something up no matter what. It is vital if you want to become a better tech you will need training. You will also need to do some self training. This can be looking at known good vehicles for scantool data, scopeshots, or maybe "bugging" a vehicle to see how it reacts. If you are not willing to do this you will not advance in this field.
The same people I see at training events all have some similar personality traits as well. Typically, we are perfectionists, inquisitive, some degree of OCD (Obsessive Compulsive Disorder), headstrong, and willing to sacrifice to be the best.
Think about it. What separates an athlete from an elite athlete? An elite athlete identifies his weaknesses and wants to improve on them. Then he/she does the work and improves. Same thing applies to our field. If you want to become a more proficient tech you will need to identify your weaknesses and take steps to sure them up. Part of that is to get as much training as possible.
So the next time a training event is around. Attend and invest in your future.
It all comes down to sacrifice and commitment. If you want to become the best in whatever you do these two actions are paramount. When I ask the same people that were wondering about training why they weren't at a recent event. I get the usual excuses "I forgot", "It was on a Saturday and I couldn't swing it", "It was after work and I didn't feel like it", "It is too expensive". These aren't as bad as the people in this industry that think they don't need any training. They know it all, just ask them. I often say the minute you think you know everything in this industry you should walk over to your toolbox lock it up and look for another job. There is no one person in this industry that knows it all. You can always learn something. If you are not learning something everyday in this industry you are not paying attention.
Some training events are better than others. No doubt about that. However, I always pick something up no matter what. It is vital if you want to become a better tech you will need training. You will also need to do some self training. This can be looking at known good vehicles for scantool data, scopeshots, or maybe "bugging" a vehicle to see how it reacts. If you are not willing to do this you will not advance in this field.
The same people I see at training events all have some similar personality traits as well. Typically, we are perfectionists, inquisitive, some degree of OCD (Obsessive Compulsive Disorder), headstrong, and willing to sacrifice to be the best.
Think about it. What separates an athlete from an elite athlete? An elite athlete identifies his weaknesses and wants to improve on them. Then he/she does the work and improves. Same thing applies to our field. If you want to become a more proficient tech you will need to identify your weaknesses and take steps to sure them up. Part of that is to get as much training as possible.
So the next time a training event is around. Attend and invest in your future.
Sunday, October 20, 2013
Parlez Vous Francais?
In the year since Superstorm Sandy hit my area. I have seen lots of flood damaged vehicles. They have seem to have come in waves. No pun intended. Right after the storm every other call was a flood vehicle. Then it seemed to die down a bit then picked up early spring and again recently. Every call always starts the same "It was a light flood it wasn't that bad". It usually ends up just the opposite. There were plenty of times I would show up look at the car and leave. I could see the waterline was at the top of the dash yeah light flood, right. The point I stress to shop owners about flood cars is the corrosion you can't see that causes the real issues. The corrosion we see at connectors is easy to see. The corrosion that occurs down the line from capillary action is another story. Salt water or fresh water it doesn't matter.
That being said I have had situations where vehicles had communication one day and not the next day. It is always an adventure. I have has some success stories. Typically, this happens when the shop understands the issues with water damage and changes harnesses instead of cleaning and praying. I treat every flood vehicle the same. First I try to get communication lines up, get the motor running, then get all the accessories going, then finally airbags. It is amazing to see the shops reactions when the vehicle starts and belches out crazy amounts of water and sand from the exhaust.
Here is one such vehicle. It is a 2006 Jeep Grand Cherokee that a shop inherited. He wanted to get it started and determine how far he wanted to go with the vehicle after evaluating how the motor ran. Most of these flood vehicles have no keys or keys that were cut to fit the ignition but not programmed for one reason or another. That was the case with this vehicle. Key was cut from a locksmith but he couldn't program it. The reason he couldn't program was the wire that feeds battery voltage from the underhood fusebox called the TIPM (Totally Integrated Power Module) to the ignition switch was rotted in the harness. I bypassed this wire temporarily and programmed the key. A few more bypasses and the vehicle started and ran. It poured sand and water out the exhaust. Overall the vehicle sounded well. I opened the drivers door and took a peek inside at the dash and saw this.
Was this vehicle from Canada? I am no linguistic expert but this is not English. It is French! I see weirdness on vehicles all the time. But, one thing is for sure Chrysler vehicles that have bad batteries or that have had batteries go low or disconnected for an extended period of time tend to have the greatest number of issues. Some will lose their VIN in modules, they will lose initialization on certain modules, set erroneous codes, etc. This is the first time I saw a language change. Time to break out the factory scantool and try to correct this language barrier.
I go into CCN (Cabin Compartment Node) which is the Instrument Cluster. Miscellaneous Functions and choose language preferences.
I update the language from French to English.
Voila!
That being said I have had situations where vehicles had communication one day and not the next day. It is always an adventure. I have has some success stories. Typically, this happens when the shop understands the issues with water damage and changes harnesses instead of cleaning and praying. I treat every flood vehicle the same. First I try to get communication lines up, get the motor running, then get all the accessories going, then finally airbags. It is amazing to see the shops reactions when the vehicle starts and belches out crazy amounts of water and sand from the exhaust.
Here is one such vehicle. It is a 2006 Jeep Grand Cherokee that a shop inherited. He wanted to get it started and determine how far he wanted to go with the vehicle after evaluating how the motor ran. Most of these flood vehicles have no keys or keys that were cut to fit the ignition but not programmed for one reason or another. That was the case with this vehicle. Key was cut from a locksmith but he couldn't program it. The reason he couldn't program was the wire that feeds battery voltage from the underhood fusebox called the TIPM (Totally Integrated Power Module) to the ignition switch was rotted in the harness. I bypassed this wire temporarily and programmed the key. A few more bypasses and the vehicle started and ran. It poured sand and water out the exhaust. Overall the vehicle sounded well. I opened the drivers door and took a peek inside at the dash and saw this.
Was this vehicle from Canada? I am no linguistic expert but this is not English. It is French! I see weirdness on vehicles all the time. But, one thing is for sure Chrysler vehicles that have bad batteries or that have had batteries go low or disconnected for an extended period of time tend to have the greatest number of issues. Some will lose their VIN in modules, they will lose initialization on certain modules, set erroneous codes, etc. This is the first time I saw a language change. Time to break out the factory scantool and try to correct this language barrier.
I go into CCN (Cabin Compartment Node) which is the Instrument Cluster. Miscellaneous Functions and choose language preferences.
I update the language from French to English.
Voila!
Sunday, October 6, 2013
2004 Lexus RX330
I get a call from a shop concerning a 2004 Lexus RX330 with 143,707 miles. Apparently the vehicle was jump started backwards and was towed in to this shop. The shop found numerous fuses blown. They corrected all the blown fuses and got the vehicle to run. The vehicle did not run well and at this point the shop is thinking the backwards jump start hurt the vehicles PCM. They pulled some codes and then wanted me to come down and either confirm or rebuke their assessment. A little background here. Toyota/Lexus PCM's I have found to be pretty tolerant to backward jump starting. The industry term is "robust". The other item of note is Toyota/Lexus PCM's are very expensive for the most part.
I arrive at the shop and start the vehicle. The vehicle starts and idles fair. Hitting the gas the vehicle stumbles to a stall. I retrieve some codes. Hmmm, all 6 Ignition Coil circuits being bad. We have a common issue. I can't see all 6 Ignition Coils going bad. But, it was jump started backwards. Or, maybe it does have a bad PCM. Let's roll up the sleeves and get some information. My mind right now is thinking we have a power issue feeding the coils. Maybe, instead of the coil primary circuit getting battery voltage it is getting a reduced voltage and that is why we have the codes and the lack of power. I got this vehicle figured out already. Yeah right.
I break out my scope. I know it will give me the most information in the least amount of time. Next is to get the "lay of the land" of what is involved. Knowledge is power so they say.
My next piece is to know the coil arrangement and the firing order.
Ok, I typically like to trigger off of #1 cylinder. But, #1 on this vehicle is buried under the intake and is a pain to get to. So I will use coil #2, it is easy. I am using Pomona test leads. I absolutely love these for testing. Secure connections, minimal damage to insulation, and well built. I get mine from AESWave.com. These guys are awesome! So the first thing I do is make sure the ground at #2 coil is good using voltage drop. It was. Then I am going to hook my scope up to Battery power, IGF, and IGT signal wires at coil #2 and start the vehicle.
Channel 1 in yellow is our battery voltage at coil #2, Channel 2 is coil #2 IGT signal (it is also what I am triggering off of), and Channel 3 is IGF at coil #2. Anything jump out at you? Well my super genius idea of low battery voltage is off the table. Battery voltage is at charging system voltage. I do see something right away.
It looks like we have a Lexus 5 cylinder. I see no deviation in battery power, no IGF signal, and furthermore the IGF signal seems low to me. Typical IGF signal is about 5 volts in amplitude. Lets add some notes. Remember, we are triggering off of coil #2. Remember the firing order.
Adding some notes it fills in the blanks. It is obvious we have issues with coil #1. But, what about that poor IGF signal? I had a theory. My theory was if coil #1 was bad enough it could pull down the IGF signal since this signal is shared amongst all six coils. How could I test my theory? I had an idea.
I reached around and disconnected #1 coil connector and restarted the vehicle. Bingo! Look at the IGF signal. More importantly the vehicle revved up well. It did have a misfire obviously but accelerated well. Let's check those codes now. If my theory was correct I should only have a #1 coil code due to it being disconnected.
Nice! Now I test battery power, ground, and IGT trigger at coil #1 connector. I explain my findings to the shop owner and recommend an OE coil unit for #1 cylinder. The unit was installed and the vehicle delivered.
To program or not to program
Part of my service is module programming or flashing some people call it. Module programming is steadily increasing as more and more modules show up in todays vehicles. Reprogramming can fix many issues but reprogramming should not take the place of good diagnostics. When I am called in to do a reprogramming I always want to know why does the shop want to do a reprogram. Many times I am called in to a shop who thinks there has to be a reprogram for the problem they are experiencing because they have exhausted all other avenues. They have changed parts-sometimes many times, checked wiring, and now they are at wits end. Here is an example. This shop has a 2004 Toyota Rav4 with 131,629 miles on it. The vehicle flagged a P2238 code related to the Air Fuel Ratio Sensor. The shop diagnosed a bad A/F ratio sensor and did a TSB search and noticed there was a PCM upgrade for that code. Toyota like most manufacturers has specific TSB's for reprogramming. In other words reprogramming is TSB driven.
Here is the aforementioned TSB. I always review TSB's thoroughly. I always make it a point to try whenever possible to get the TSB from the manufacturers website as well. Reason for this is they have the latest information. Maybe, there was a change in procedure, etc. Using the manufacturers website information assures me of the latest and greatest information. I also scan the vehicle as well with my tooling. It is not that I do not trust my customers. It is just assurance that we are going in the right direction. It also gives me an opportunity to see if we have other issues.
Ok, here we have it. The next procedure is to see what calibration is currently in the module. Then compare it to the TSB information.
It is the old calibration that needs updating. Normally, I use Toyota Techstream to program. This shop had sketchy internet and the calibration I needed I had on a Toyota Calibration CD. Toyota no longer uses Calibration CD's. Like most manufacturers it is all web driven. I will have to get out my J2534 reprogramming equipment. I am not a big fan of J2534 programming. I like to use factory tooling. In this case I felt confident using it.
Here is a laptop with proper software loaded on it and the J2534 interface. It is important to use an approved interface. All manufacturers will list them on their websites.
Here is another essential tool for programming whether it be J2534 or factory tooling. A battery maintainer. This one is the Midtronics PSC-550. It is pretty much the industry standard. It carefully maintains battery voltage at 13.4 volts with no ripple that you would get from a regular battery charger. The process of programming is menu driven. You have to pay attention! Key cycles have to be done in the allotted time. Let's begin. This flash took about 14 minutes.
This is the after screen showing the previous calibration and the new calibration. It also shows that it was successful. Like anyone in my business it is not successful until it starts and runs. Most importantly it solves the concern.
I check for codes after we start and run the vehicle. Looking good so far.
I always check if the calibration was really updated.
Here is the aforementioned TSB. I always review TSB's thoroughly. I always make it a point to try whenever possible to get the TSB from the manufacturers website as well. Reason for this is they have the latest information. Maybe, there was a change in procedure, etc. Using the manufacturers website information assures me of the latest and greatest information. I also scan the vehicle as well with my tooling. It is not that I do not trust my customers. It is just assurance that we are going in the right direction. It also gives me an opportunity to see if we have other issues.
It is the old calibration that needs updating. Normally, I use Toyota Techstream to program. This shop had sketchy internet and the calibration I needed I had on a Toyota Calibration CD. Toyota no longer uses Calibration CD's. Like most manufacturers it is all web driven. I will have to get out my J2534 reprogramming equipment. I am not a big fan of J2534 programming. I like to use factory tooling. In this case I felt confident using it.
I always check if the calibration was really updated.
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