I was called to a body shop for a complaint on a Dodge Durango that was in a front end collision (Figure #1)
.
The truck suffered only minor damages but the end result was a complaint of an ABS light on. The body shop did
inspect all the wheel sensors for visual damage and made sure the ABS module was properly latched. They also
checked all the fuse panels for blown fuses. The body shop did not have a scan tool to retrieve any onboard
service codes so I was called in for assistance.
It is not uncommon to have a body shop that does not own a scan tool or even hire a diagnostic tech to resolve
onboard computer issues. Most of these body shops will use a test light and some old school tactics to get by.
This is not their fault because even if the body shop employees invested in diagnostic equipment or diagnostic
training there would be no compensation for their efforts because diagnostic time is usually not allowed in
estimates. Their job function is strictly to put these damaged vehicles back together the way they were built
at the factory. This task alone is a huge project involving such precision work and patience. When the car is
completed all the onboard controllers will do an integrity check of the vehicle and if there are any problems
they are guaranteed a service light to illuminate.
When I arrived at the shop I started the vehicle and noticed that the ABS light was the only lamp illuminated.
I next connected my Chrysler Star Mobile to scan the ABS module and pulled a code C2202 (Figure #2-Original
VIN Mismatch/Missing)
.
This code by its description alone indicated to me that the internal ID of the
ABS module did not match the internal ID of the PCM. A lot of manufactures will store all the vehicle configuration and
VIN into the PCM, and other modules on board may be required to match the PCM. This is why you can not simply
place a new or used module on board without holding a welcoming party to make sure this replacement module is
properly set up. There is usually a mass of confusion among my garages about reprogramming a module so I need
to clear the air here.
Setting up a module may require up to 3 different procedures. The 1st procedure may be as simple as installing
just a VIN # and this is part of a Configuring/Coding procedure. When entering a VIN you need to be very careful
and make sure you are wearing those special bifocals to enter the correct letters and numbers because some
manufactures may only allow a new or rebuilt module to VIN once. After that the module is locked and you own it.
The next part of the Configuration/Coding procedure is to enter the proper options for the vehicle. This may be
done through a series of Yes/No selections, entering Tire/Axle Ratio, entering a vehicle specific 4-7 digit
coding # or by going through a lengthy process of string coding of as many as 50 2-4 digit numbers. The 2nd
procedure is the actual Reprogramming phase that involves the loading of operating software into the module.
This software is usually available from a manufacture website as a download or from a manufacture CD subscription.
To install the software a user would need a generic J2534 compliant device or a factory scan tool to be used
as a pass-thru device. This software is usually VIN specific and is updated as needed by the manufactures to
resolve vehicle glitches. The 3rd procedure I call Adaptation. This is a procedure to relearn the computer so
that it may properly control the vehicle. This procedure may include relearning throttle angle, crankshaft
position, fuel trim, steering angle position, occupant seat weight, power window position or theft key ID. Now
that I have made you familiar with the process we can now move on to the next diagnostic check
I wanted to view the entire network to see what the other controllers on board were seeing and to get more clues
so I could dot the I’s and cross the T’s. I selected the All DTC’s menu (Figure #3)
and discovered that the ABS controller was not the only one pointing a finger. The CCN, FCM and ORC also complained of a VIN Mismatch as
well as a configuration error. This now ruled out the ABS as a possible suspect of a wrong installed or configured
module because too many network fingers were pointing in the direction of the PCM. The body shop told me that
they never replaced any controller on board. They also called the owner of the vehicle who stated that
“There never were any lights on before the accident”. But you know how that goes. So my next move was to go to
the PCM Miscellaneous Functions menu to check the PCM VIN. When I did this I was surprised to see the “This VIN is
Invalid” results (Figure #4)
.This was not a case of a wrong VIN but one that was corrupted. The first 2 characters of the VIN were actually
vertical space bars. There was no way someone could have typed these in to the PCM because the factory tool does
not supply these characters as a selection and the scanner would never validate such an entry. The only possibility
that I could come up with is maybe when the battery went completely dead the VIN defaulted to a corrupt insertion
of VIN characters. There is also a good possibility that the nonvolatile memory of the PCM could not hold its
information properly after a loss of keep-alive power. I selected Next and entered the correct VIN characters
(Figure #5)
.
I proceeded to the following step and the Star Mobile validated the VIN as a
good entry (Figure #6)
.
I now went back into the View All DTC’s menu and cleared the entire network of error codes. I started the
vehicle three times in a row with 10 seconds on and 10 seconds off to allow all controllers on board to perform
a 3 Trip integrity check and the ABS light was now extinguished. As a final check I went into the main ECU View
menu (Figure #7)
and there were no codes stored in any controllers.This vehicle was a perfect example of how a shop can be married to a vehicle even if a job was performed in a
flawless reassembly. When a vehicle battery is disconnected for a long period of time most vehicles will need
to go through a series of relearn procedures. Some of these procedures may even require a factory scan tool to
perform these tasks. Configuration and Coding information is usually held in nonvolatile memory of a controller
and should not be lost in battery power loss situations. I have seen many cases of controllers defaulting to
factory options but have never come across one with a corrupted VIN. Even as I was writing this story I came
across a 2004 Dodge Durango with a complaint of a Tire Pressure Monitor light on (Figure #8)
after a battery was disconnected. This vehicle was not equipped with a TPM system on board. There were also 6 codes stored in
the Cabin Compartment Node pertaining to heated seats that the vehicle did not have (Figure #9)
.
The only fix was to connect the Star Mobile to Chrysler's server and perform a vehicle restoration using the Vehicle
Preparation menu found in the scan tool (Figure #10)
.
Hope this story will shed some light to help you through a similar adventure.