Accessing and Reading Diagnostic Trouble Codes

ENTERING SERVICE MODE
To enter diagnostic mode, proceed as follows:

1. Turn the ignition ON.
2. Depress the OFF and TEMP UP switches on the Electronic Climate Control Panel (ECCP) simultaneously and hold until all display segments light. (Segment Check)

NOTICE: Operating the vehicle in the Service Mode for extended time periods without the engine running or without a battery charger will cause the battery to run down and possibly relate false diagnostic information, or cause a no start condition. To ensure proper operation, attach a battery charger, if vehicle is to be operated in Service Mode without engine running for periods longer than 1/2 hour.

DIAGNOSTIC DISPLAY
During diagnostic operation, all information will be displayed on the Season and Trip Odometers of the Instrument Panle Cluster (IPC), unless otherwise noted.

Due to the limited display space available, single letter identifiers are often used for each of the major computer system. These identifiers are:

E for ECM, B for BCM, I for IPC, and R for Supplemental Inflatable Restraint (SIR).

DIAGNOSTIC TROUBLE CODE DISPLAY
After diagnostics is entered, any diagnostic trouble codes stored in computer memory will be displayed on the season odometer. Codes may be stored for the ECM, BCM, or SIR systems.

Each diagnostic trouble code consists of the system abbreviation (E,B, or R), a three digit code, and the letter C or H. All codes for each system are displayed together, in the order of their three digit number (lowest first - i.e. E013, E014, etc.). The final digit of the code, a C or an H is used to indicate whether the code is current or history. C means the fault was still present the last time the diagnostic test was run, while H means the failure was not present the last time the code was tested for.

If no codes are present for a system, a NO X CODE message (with X being the system abbreviation - E, B, or R) will be displayed. If the communication line to a component is not operating, a NO X DATA message will be displayed, indicating that the BCM could not communicate with that system at any time during the display of codes, if the FAN DOWN button on the Electronic Climate Control Panel (ECCP) is depressed, the display of codes will be bypassed.