Airbags, Airbags, Airbags Part 1

I get a fair amount of calls from body shops. Most of the times it is collision related issues such as airbag or wiring issues. I am going to give you three of my most recent. Here is a 2011 Hyundai Sonata. The vehicle was in a recent accident. The shop did a nice job putting this vehicle back together. Along the way components in the restraint system were changed-airbags, seatbelts, and the airbag control unit. The shop called me after they changed the items and had a flashing airbag lamp with key on. Starting in approximately 2009 on Hyundai/Kia vehicles the airbag control unit has to be variant coded for it to operate properly. The airbag control unit has to be "programmed" so it knows whether it has side curtain airbags, etc. The flashing lamp tells you that no variant coding has been set.

This can only be done with the proper tooling. It is a one shot deal. Here is the G-scan made by a company called GIT. While this is not the true blue factory tool for Hyundai/Kia (The GDS is the factory) it really comes a close second. In fact it will do everything GDS will do minus programming and fault guided diagnostics. Rumor has it that engineers for Hyundai/Kia have "super" G-scans that will actually program. My G-scan is actually a loaner from my good friend Joey "Bag o donuts" for which I am grateful for. He knows I do a great deal of Hyundai/Kia work and he has a love/hate relationship with this scantool. Mostly hate.

After building the vehicle and the system I want to access we get this screen. I choose Vehicle S/W Management.

This is next screen. I have already called my source to get the correct variant code for this vehicle using the VIN. You have to have a source at the OE level to retrieve these variant codes.

This is the next screen detailing the function and where you should have the ignition key. lets hit ok.

The next screen includes a mini keyboard for inputting the variant code. The tool includes a stylus that helps with this.

After inputting the code this screen just informs you the procedure is complete. I turn the key off for 1 minute or so. Turn the key back on and no more flashing lamp. I perform a WCS (Weight Classification System) rezero procedure with the G-scan and clear all codes. Finally, I check the operation of the passenger weight system for proper operation and do a final scan for codes.

Next up is a 2006 Mercury Milan that was involved in a collision. Again, various components of the restraint system were changed including the Airbag contol module which Ford calls the RCM (Restraint Control Module). Typically, when a Ford module is changed the information from the old module is retrieved using a procedure called PMI (Programmable Module Installation) and then uploaded to the new module. Unfortunately, we do not live in a perfect world. Sometimes the module is missing or damged and information cannot be retrieved. Ford has an answer for this called "As Built Data" using the VIN. Here in the above screenshot with my Ford IDS we have a B2477 in the RCM. The RCM is not configured or configured properly. Since I have no module to retrieve data and the vehicle is already together I will use As Built Data to configure this module. I will need the full 17 digit VIN and access to www.motorcraftservice.com.

This is the As Built Data entry screen. I enter the full VIN.

Airbags, Airbags, Airbags Part 2

This is what you get. I purposely cropped the top of this. Above is the VIN number and more modules. The modules have BCE addresses. These addresses correspond to certain modules. I know that 737 is for the RCM. I then print this out and start the PMI process with my IDS.

This is the screen you get. Just follow very carefully the lines and input the characters exactly. Hit the blue checkmark on the lower right and the screen will advance to the next set you need to input. When you input all the characters you will get this.

Next we will check for any codes. Now that the RCM is configured now it can self test the system properly.

The system is operational. I will clear the continuous codes finally. Here again I do passenger seat rezero procedure and check for proper operation.

This is a 2011 Mazda 3 Wagon that the shop correctly diagnosed a bad passenger presence module. They changed the module and related wiring. They still had an airbag lamp on and this code. I am using my Mazda IDS system. This code can be set two different ways. One if the OCS (Occupant Classification System) is not calibrated or loss of communication between the OCS and the RCM. Let's see how we can tell the difference.

I call up some pids on the RCM to help me out. I can plainly see we have no communication faults but we have a calibration fault. To be fair you can also use LFC (Light Flash Codes) to differentiate this as well. I hate reading LFC-blink and it is time to restart. So now I have to do a OCS calibration. This involves using my Mazda IDS and some weights on the passenger seat. The procedure is pretty lengthy and must be done in a controlled manner after the vehicle sets for awhile depending on temperature. After the calibration procedure is complete lets rerun the self test.

System passes and the airbag lamp goes off. Consequently, the B1013 you see I induced when I performed the self test with some weights still on the passenger seat. Note to self have nothing on front passenger seat when doing a self test. Clearing the CMDTC's and we are set.

2001 Cadillac Seville SLS

There she is. One 2001 Cadillac Seville SLS with 103,361 miles on it. Pretty clean car. Unfortunately, it does not start, nor crank, nor does the host of electronic gadgetry on this car work. The owner says sometimes he can disconnect the battery and reconnect and vehicle it will start and perform well. Notice the battery charger in the picture. Usually, a clear indication to me that the battery in the car is a paperweight. I see a ton of bad batteries. People will have expensive stereo systems, fancy alarms, and they have a bad battery. They don't mind jumping the car 5 times a week. That spells disaster to electronics. Between, voltage spikes and the eventual backwards jump start it gets ugly fast. Let's get the show on the road with this car.

I hook my Tech2 to see what modules are reporting. I choose Class 2 DTC Check to see what is going on quickly.

This is what I get. Now, this could go many ways here. These vehicles have lots of issues. Bad ignition switches, water leaks soaking modules and causing communication issues. On this model I know that they typically will have windshield and/or passenger door leaks and the SRS (Airbag) module under the passenger seat gets soaked and causes issues. A quick feel under the seat and it feels pretty dry. I then break out the scope and check pin #2 at the DLC and get a constant 12v. The Class 2 communication line is shorted to power. So many things can cause this-bad modules, shorted harnesses, poor grounds. Lets look at the Class 2 line.

Here is part 1.....

Here is part 2. Lots of modules here which is to be expected on a Cadillac. These modules are arranged in a Loop pattern. GM has 3 different ways to arrange Class 2. Loop is what you see here where communication lines go in and out of every module. Star arrangement where each module generally has one communication wire going to it and there is usually a splice pack where you can take one module off at a time. Finally there is Star/Loop which combines the two. Loop is great for redundancy but can be a little more intensive to diagnose. I like to start with easy. I visually check grounds and harnesses for rubbing or damage. They look pretty good. Next, I start disconnecting modules, cycle key and then look at my scope on Class 2 for activity. I disconnect ABS no luck. Every other module is buried except one-the PCM.

I unearth it and disconnect both connectors.

This is what I have at pin #2 at the DLC now. Perfect Class 2 waveform. Let's recheck the modules with the Tech2.

Nice! I now have modules reporting. The only module not reporting is the PCM. Obviously, it is hanging in the breeze. A quick check of powers, grounds, and 5vref at the PCM reveals no other issues. This PCM is the cause of the Class 2 being shorted to power. Remember, the battery charger, etc. I inform the shop owner of my findings and give him options so he can discuss with this customer. He calls me the next day and tells me money is tight with the customer. He wants to go with a used PCM and still does not want to change the battery. I do not mind setting up used modules as long as it will not cause issues. Be careful. Sometimes replacement of used modules will cause issues. Ask one shop I got called in when they changed a BCM (Body Control Module) on a Caravan to fix a rear wiper issue. Well after the used BCM went in the vehicle got infected with VTSS (Anti theft) and the mileage almost doubled with no going back. Try explaining that to the customer. Be careful! All my customers know to call me first and ask me about used module beforehand. It is something I preach. Ok, so we are going to be putting a used PCM in this Cadillac. New, reman, or used it will have to be setup with proper VIN and calibration. As well as the theft system relearned.

Used PCM installed. Still have great communication. Next....

I hook up my Midtronics battery maintainer to the battery. Not because this vehicle has a bad battery. I will not reflash, program, etc without it. It is a ripple free battery maintainer that holds voltage steady at 13.4v. It is endorsed by GM and has been the industry mainstay for some time. I know guys that flash with jumpacks or battery chargers. I do not have that kind of luck. There is a lot of data being transferred and I want to make sure I have done everything for a successful flash event. A quick check with my DVOM at the battery tells me we have stable proper voltage. Next, I hook up the Tech2 and request info from the used PCM. It will have the VIN and calibrations from whatever vehicle it came out of. I will be overwriting that with proper VIN and calibrations for this vehicle.

I then hook up my Tech2 to my TIS2000 program, input the proper VIN and choose replace and reprogram PCM. This is what is called remote programming. It is when you are downloading calibrations to the Tech2  from the laptop then disconnecting and using the Tech2 stand alone to update programming. Sometimes I use this method other times I use pass thru. I avoid flashing/reprogramming with a J2534 tool whenever possible. I like factory tooling. Less pitfalls and suprises.

There are the correct calibrations. I upload to the Tech 2 and go back to the car.

Here is where it gets a little dicey. These Cadillacs along with certain Corvette models (check your service information) really should be programmed by themselves. Apparently, with so many modules on the communication line if one of them "talked" while a programming event was going on it could corrupt the programming. So GM recommends to reprogram these PCM's with a special stand alone harness that isolates the PCM. Others, I know have made jumper harnesses of their own to work around this. I had some good information that if I pulled the I/P fuse in the underhood fusebox that the chatty modules involved would go to sleep and I could program this PCM. So I did.

Here I rechecked. Sure enough my chatty modules are no longer reporting and the PCM is there. A quick recheck of proper voltage and connections. Lets program!

Here we go.

A couple of minutes later. Lets recheck for proper calibrations.

Bingo. Vehicle still is not going to start. We need to relearn theft.

Here we have a choice to relearn theft. GM typically gives you two choices. One is a long way typically 30 minutes which involves turning key on and waiting, etc. The second way is a program that will run that speeds things up. That is what I use. Again, we request info from vehicle using the Tech2. This time VIN is correct.

I choose theft relearn and upload it to my Tech2.

This is a lot faster. After completion the vehicle starts and runs properly. I clear all codes and make sure to perform any after reprogramming procedures such as oil life reset, crankshaft variation relearn, etc. The Cadillac rides again. Hopefully, that battery gets changed sooner rather than later. 

  

   
   

Korean Chaos

Well, it has been a long time since I last posted and I would like to catch up. Thankfully, business has been good and I have had little downtime. Here is a 2004 Kia Optima with a 2.4 liter 4cylinder motor. I see a ton of Hyundai/Kia vehicles in my area. They are very popular. The shops concern is the vehicle seems to run pretty decent with a slight lack of power but once warmed up has a very shaky idle. There no codes. I first look at some fuel trims which seem to be acceptable. I road test the vehicle and no doubt it is slightly underpowered and indeed has a shaky idle. I decide to look at engine vacuum to start with because the vehicle feels like the EGR valve is stuck on at an idle.

As you can see 14" of vacuum at an idle. I normally see these vehicles produce 19" of vacuum on a good running vehicle. The low vacuum is a clue. The next thing I do is feel the EGR valve with the vehicle running. It feels pretty cool the touch. Now, this is not an absolute foolproof diagnostic test. However, typically if an EGR valve is flowing some exhaust gases it will be warm to hot to the touch at an idle. Warning, do yourself a favor hit the EGR with a non contact laser thermometer first before putting your hand on it. Ok, EGR not flowing at an idle, what is next?

I like to scope things. I feel it gives me the best bang for the buck. In my business remember I need to be fast and efficient. I want to look at crankshaft sensor to camshaft sensor patterns and how they correalate to each other. If you notice the cam sensor is driven off the exhaust camshaft of this car.

Here is the CKP sensor pattern in yellow on channel 1 and the CMP sensor pattern on channel 2 in green. Call it my OCD or whatever I typically always use channel 1 for CKP sensors, it keeps captures consistent. Ok, is this a good pattern? This is where data acquisition comes into play. So I pull up a known good waveform from my library.

Here again CKP is channel 1 in yellow and CMP is channel 2 in green. What I can see immediately is that the Cam sensor pattern either intersects the Crank sensor pattern halfway or straddles it midway. Lets revisit the vehicles waveform at a different timebase.

It is shifted no doubt. Be careful using this method. The pitfall is that the Cam sensor is only on one camshaft. So we could have a situation where one camshaft that drives a sensor is in time and the other that has no sensor is off. When presented with that situation I use running compression with a pressure transducer and look at exhaust and intake valve opening events. Here, I didn't have to. I advised the shop to check timing belt alignment. Sure enough they called me back later that day after resetting the timing belt. The vehicle performed and idled well.

I recently was at a shop that just did a timing belt replacement on a 2004 Hyundai XG350 3.5 liter v6 with 75,136 miles as part of routine maintenance. The vehicle ran well into the bay. Unfortunately, it ran quite poorly after the service. It was setting misfire codes and had a terrible lack of power and a rough idle. These cars normally idle like glass and perform quite well.
The tech that did this job was sickened. He is a very thorough tech and I have been there a couple of times in my life where the vehicle ran worse after I serviced it. It is a bad feeling. I really felt for him. I went over the timing belt procedure with the tech and on the car several times. I often find that more can be found out asking questions than looking at the car. After some head scratching the tech said something that stuck with me. He said he had a hard time seperating the crank pulley from the crank sprocket. With this I broke out the scope and decided to check CKP/CMP correalation. I had a hunch.

Here again CKP in yellow and CMP in green. I didn't have a known good pattern handy. But, I felt very confident that it would follow suit like the Kia previously. Here, is another shot.

Cursor 1 is where the rising edge of the CMP sensor is and cursor 2 is where it should be. I know what happened. I tell the tech to get the timing belt off and remove the crank sprocket and CKP interruptor ring behind the crank sprocket.

Here is the interruptor. Those blades pass through the CKP sensor causing the square wave pattern. If you notice there are two dimples on the ring that should not be there.

Here is the backside of the crank sprocket. The two protrusion tabs that should go into the holes on the CKP interruptor ring are worn off.

Here is how it fits together. What happened here is when the tech was seperating the crank pulley from the sprocket it pulled the crank sprocket forward and disengaged the CKP interruptor ring from the crank sprocket. When the tech reinstalled everything it moved and therefore corrupted CKP/CMP timing. This caused the vehicle to run like the timing was retarded drastically. This was very easy to do. Hyundai does not extend the crankshaft woodruff key all the way in and relies on these two small tabs that are easily broken to index everything. One new crank sprocket and interruptor ring and away it went.       
 
 

2001 Nissan Pathfinder

Here is one 2001 Nissan Pathfinder with 141,893 miles on it that is due for state inspection. The dilemma is the vehicle has the dreaded P1320 code for primary ignition. This is a very common code on Nissan vehicles with COP (coil on plug) ignition. There are three items that I see that will cause this code. One is bad COP units (more on this later), wrong spark plugs, and someone has tied the rpm input for a remote start into one of the COP units. The shop owner asked me to look at this because the customer cannot go for 6 new COP units. He needs a definitive answer on how many COP units are bad and if other issues are at hand. The code set criteria for this code is a little misleading. Basically, it says that there is a missing primary signal. So, this vehicle should be missing, right? Well, this vehicle runs well with no apparent misfires. Time to pull a wiring diagram.

Here is two out of three pages of wiring for the ignition system. It shows that the power for the COP units comes from one contact of the ECM relay. I am only showing three of the six COP units. Those of you that know me and follow the blog know where I am going next. What is going to show me all six COP units in great detail.

Out comes the low amp probe. I make jumpers for both contacts of the ECM relay and I am going to trigger off of #1 COP control circuit.

You don't have to be a scope jockey to see that two amperage patterns are different from the rest. The yellow trace is the coil amperage and the green is the #1 trigger. Forgive my forgetting to zero my probe. Let's add the firing order which is 1-2-3-4-5-6.

As you can see cylinder #1 is lower than the rest and cylinder #4 is higher. These are our two odd men out. Even the pattern at this timebase is not the same as the other four COP units. A good healthy COP unit on this application is typically 6-8 amps. Number 1 is at 4 amps and number 4 is at 9 amps plus. Lets look at these two and a healthy one closer at a better timebase.

Here is number one. Looks to me that there is an issue with this COP unit that is also affecting the trigger. More evidence to condemn the COP unit. Let's look at number four.

A couple things become apparent here. The amperage is high and the ramp is rather straight. Not, what I typically see. Let's look at a good cylinder.

Now, that is a typical Nissan COP waveform. Notice the ramp pattern and amperage. Again, forgive me for not zeroing my probe.

So here we are twenty minutes later and we have a definitive answer for the shop owner. I advised him that cylinders #1 and #4 COP units are the reason for the P1320. I also advise him to check the plugs while he is there. At this point I also tell him do not be suprised if these COP units at #1 and #4 have been changed and are aftermarket units. Sure enough the shop owner calls me the next day and tells me both units were recently changed with aftermarket units. He installed OE units, checked the plugs for proper brand and gap, and test drove the car. He was able to run and satisfy all the monitors for inspection and both he and vehicle owner were very happy. The MIL was out and a sticker was issued. At this point here goes my rant. The aftermarket in it's ongoing quest to provide "cheap" parts has shot itself in the foot. I see this time and time again. Quality doesn't cost it pays. The extra coin for an OE part is money well spent. Here is a prime example.