Clearing Diagnostic Trouble Codes

On-Board Diagnostics Diagram - Part 1 Of 2:

On-Board Diagnostics Diagram - Part 2 Of 2:

Instrument Panel Cluster:

OPERATING ON-BOARD DIAGNOSTIC SYSTEM
To enter diagnostic mode, proceed as follows:

1. Turn ignition "ON".
2. Depress the "OFF" and "WARMER" buttons on the Climate Control Center (CCC) simultaneously and hold until the segment check appears on the Instrument Panel Cluster (IPC).

SEGMENT CHECK
The purpose of illuminating the IPC is to check that all segments of the LED displays are working. The turn signal indicators DO NOT light during this check. If any of the segments are inoperative, the affected display panel will need to be diagnosed.

TROUBLE CODE DISPLAY
After the segment check, any trouble code stored in computer memory will be displayed. Codes may be stored for the PCM, IPC, ACP, or SIR systems.

If no codes are present for a system, a "NO X CODE" message (with "X" being the system i.e. E, I, A, R, T or S) will be displayed. If the communication line to a component is not operating, a "NO X DATA" message will be displayed, indicating that the IPC could not communicate with that system.

At any time during the display of trouble codes, if the "AUTO" button on the IPC is depressed the system will exit "Service Mode" and go back to normal vehicle operation.

SELECTING THE SYSTEM
After trouble codes have been displayed, a specific vehicle system (PCM, IPC, ACP, SIR, TCS, or RTD) may be selected for testing.

The first available system will be automatically displayed (i.e. PCM?). While selecting the system to test, any of the following actions may be taken:

1. Depressing the "HI" button on the CCC will select the displayed system for testing.
2. Depressing the "LO" button on the CCC will display the next available system selection. This allows the display to be stepped through all system choices. This list of systems can be repeated following the end of the system list.
3. Depressing the "OFF" button the CCC will stop the system selection process and return the display to the beginning of the trouble code sequence.

SELECTING THE TEST TYPE
Having selected a system, the first available test type will be displayed (i.e. PCM DATA?, PCM CLEAR CODES?). While selecting a specific test type, any of the following actions may be taken:

1. Depressing the "HI" button on the CCC will select the displayed test type. At this point the first of several specific tests will appear.
2. Depressing the "LO" button on the CCC will display the next available test type for the selected system. This allows the display to be stepped through all available test type choices. This list of test types can be repeated following the display of the last test type.
3. Depressing the "OFF" button on the CCC will stop the test type selection process and return the display to the next available system selection.

CLEAR CODES
Selection of "CLEAR CODES?" test will result in the message "CODES CLEARED" being displayed along with the selected systems name. This message will appear for 3 seconds and then return to the next available test type.

EXITING DIAGNOSTIC MODE
To get out of the diagnostic mode anytime during the test, depress the "AUTO" or "DEFOG" button, or turn the ignition switch "OFF". Trouble codes are not erased if this is done prior to selecting "CODES CLEARED".