Body computer to verify mileage.

[olbuickman]

Awhile ago I thought I saw a post that you could verify your cars actual mileage by checking the body computer. Is this the computer located behind the glove box? If in fact this is the way, how would you go about this procedure. Thanks,Frank <img src="http://forums.aaca.org/images/graemlins/smirk.gif" alt="" />

[Jim]

It can only be done on an '88-89 with the touch screen. On the '90-91s the procedure is similar but the information reads out in the area where the mileage normally is and reading the vin is not an option. You verify that the vin read out on the screen is the same as up by the windshield and if it is your mileage is correct. If the vins do not match then your BCM and/or PROMS have been changed and the mileage reading you are seeing is of the BCM in your car and not the original.

The following is the procedure for checking the codes but the last step after it asks you if you want to clear the codes, if you say "no" to that question, is it will read out the vin when doing the "B" codes.

BCM means Body Computer Module and controls the functions of the body.

ECM means Engine Computer Module and controls the functions of the engine.

IPC means Instrument Panel Cluster.

With the key on, engine running or not, go the climate screen on the

CRT and press and hold the off and warm buttons at the same time.

The service engine soon lamp will light and the ECM codes will be listed

followed by the BCM codes and then the IPC codes.

They go by quite fast so you may want to write them down. Any code with a

"h" after it will be a code that was current, but is not now, and is listed

a "history" code. Any code that does not have an "h" is a current code.

ECM codes will start with a "e" and then 2 digits, BCM with a "b" etc.

After the codes are listed the screen will say ECM? This means do you want

to diagnose the ECM.

If there were "e" codes push "yes" if not, push "no" and the screen will

go to the BCM?

If there are ECM codes after pushing "yes" it will ask several questions.

Keep pushing "no" until the question "ECM code reset" comes up and then

push "yes".

You can go from the ECM to the BCM and then to the IPC and clear any codes.

You can't hurt anything by doing this procedure and even if you make a

mistake simply push "end" or shut off the key and everything will go back

to normal.