To check for Diagnostic Trouble Codes stored in the computer, turn the ignition on, then hold down the OFF and WARMER (for digital dash) or OFF and passenger-WARMER buttons (for analog dash) or OFF and "Info ^" buttons (if you have temperature dials) until all of the dash lights come on. The digital display will then show any codes stored. Be prepared to write them down. When it's done, you will probably see "PCM?" At that point, press the OFF button 3 or 4 times until the dash goes back to normal, or just turn off the ignition.

Remember, when in the diagnostic mode the LOW FAN button becomes NO and the HIGH FAN button becomes YES to the prompts. To clear the codes answer NO until you see CLEAR CODES? Then answer YES.

If you've checked for codes and found some, this is what you need to look up what they mean:

If your car is a 1996 model or newer, go here: (OBDII) (P codes only, but with diagnostic help)

This link includes ALL OBD-II codes (P, B, C, and U codes)

If your car is 1995 or older, go here (OBDI)

Once you have looked up what the codes mean using the web sites listed above, you may be able to figure out exactly what needs to be done by the definition of the code. If you have any questions on what it means or how to fix it, come back to your forum question and post the code and the definition. More than likely, someone will be able to tell you exactly what needs to be done. We will do our best to help.

Good luck!

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Courtesy of JimD

DTC display; 1998-2004 Seville, 2000-2005 Deville and other models with 3 buttons on the RH side of DIC

Use the 3 switches located to the right (LH drive cars) of the Driver Information Center (DIC) to activate and respond to the OBD prompts on the DIC.

INFO DOWN or INFO UP = manual toggle

Ignition ON, acknowledge any warning messages; press ON/OFF and INFO UP together for 2 to 3 seconds. Everything in front of you lights up for 4 or 5 seconds, then you will see:

Display shows "ALL?"

Answering YES will display "ALL CODES?"
Answering YES will run automatic test sequence and display codes, if any. Systems and codes will scroll faster than I am able to read them and write them; not to worry.
"ALL CLEAR CODES?" will display at the end of the automatic test. If you are satisfied you have the information you need, answer YES to clear/erase all error codes.

Answering "ALL?" with INFO DOWN will toggle systems test manually in order.
Answering "ALL?" with INFO UP will toggle system test manually in reverse order.

Press INFO RESET to reset DIC to "ALL?" to start again.

Ignition OFF to exit.

SYSTEMS: (as of 1998)

ABS (Antilock Brake System)
AMP (Amplifier)
DDM (Door Driver Module)
DIM (Dash Integration Module)
IPC (Instrument Panel Cluster)
IPM (Instrument Panel Module)
IRC (Integrated Radio Module)
PCM (Powertrain Control Module)
RFA (Remote Function Actuation)
RIM (Rear Integration Module)
SDM (Sensing and Diagnostic Module) Includes airbag crash data. Under RF seat
VTD (Vehicle Theft Deterrent)
MSM (Memory Seat Module)
TTM (Tilt/Telescoping Module)
RSS (Road Sensing Suspension)

"History" means that the fault is no longer detected. It will stay in history for 50 ignition cycles then be deleted unless it becomes "Current" again or is cleared manually.

If you need advice after a code pull, post your found codes and their definitions in your proper forum.

How to video.