ORIGINAL: Skotty

I discovered that it's not very easy to find information online about how to read OBD-II trouble codes / error codes for my 1997 Seville using the dash controls. Here is what information I was able to find either through web searching or experimenting -- bearing in mind that equipped options could result in slight differences in how it works:

Buttons on the dash you use:
OFF - the OFF button that turns off climate control
WARMER - passenger-side climate adjust up, or adjust WARMER
FAN_UP - the up button for the fan
FAN_DOWN - the down button for the fan

1) Turn ignition to ON
2) Simultaneously press and hold the OFF and WARMER buttons.

At this point, all the dash lights should light up, and trouble codes will appearing on the dash display one at a time, with a short time delay between each code. They will be displayed in order by system. This step can be skipped by pressing a button -- but I forgot which -- either the FAN_UP or FAN_DOWN. Sorry I don't remeber which.

After the codes all cycle through, the dash will read "PCM?". You are basically at a simplistic menu at this point, where you can switch between systems and read codes, clear codes, or do a few other things.

The buttons at this point operate as follows:
FAN_DOWN - cycle through the options in the current menu
FAN_UP - select the current menu item
OFF - back up to prior menu. At root menu, pressing OFF exists diagnostics.

The systems I am aware of are as follows (in order):
PCM - Powertrain Control Module
IPC - Instrument Panel Cluster
ACM - Air Conditioning Module
SDM - Inflatable Restraint Sensing and Diagnostic Module
TCS - Traction Control System
RSS - Road Sensing Suspension
PZM - Body Control Module
IRC - Integrated Radio Chassis
RFA - Remote Function Actuation
CCP - Climate Control Panel
MSM - Memory Seat Module
MMM - ?

You may not have some of these options, or there may even be more options, depending on what options your car is equipped with.

I researched this to figure out how to reset the COMPRESSOR OFF / VERY LOW REFRIGERANT message without having to unhook the battery. I've been working on my AC and the AC pressure sensor has been acting flakey. Now I can just turn on diagnostics, go to the ACM menu, press FAN_UP, go to the clear codes option, press FAN_UP, press OFF a couple of times to exit. Much nicer than having to unhook the battery every time. Enjoy.

You can find some of this information, and other information such as a codes list at the following site: http://myweb.accessus.net/~090/dtcobd2c.html