Accessing and Reading Diagnostic Trouble Codes

Description:

Flash code diagnostics must be used to identify the diagnostic trouble codes (DTCs) that are stored in the EBCM's memory. Flash code diagnostics cannot be read if the "BRAKE" warning lamp is steadily illuminated (by low brake fluid or an engaged parking brake).

CAUTION: Park the vehicle in a level area and place chocks in front of the front wheels and behind the rear wheels. This action will prevent the vehicle from moving while RWAL diagnostic procedures are being performed. Failure to follow this procedure could result in personal Injury or system damage.

To enable flash code diagnostics, release the parking brake and check to make certain that the brake fluid level in the reservoir is adequate for normal system functions and proper "BRAKE" warning lamp operation. Turn the ignition switch to "ON." Using a service jumper wire, short together terminals 3 and 5 of the rear wheel antilock data link connector (RWAL DLC) for more than 2 seconds. Remove the jumper wire, observe the "BRAKE" warning lamp and read the DTC.

Each DTC consists of some short flashes and a final long flash. Count the flashes, including both the short ones and the final long one, for DTC identification. Be sure to read the DTC several times to be sure that the proper one is identified. Once the flash code diagnostic mode has been enabled, the flashing continues until the ignition switch has been turned to "OFF."

If the ignition switch is turned to "OFF" before the DTC is identified, it will probably be lost. There may be cases where a hard fault exists and the DTC will reappear after the ignition switch is again turned to "ON" but, in most cases, the driving condition that produced it will have to be created.

If the problem only occurs intermittently, the DTC may be extremely difficult to reproduce. Therefore, it is strongly recommended that all DTCs be fully identified before the ignition switch is turned to "OFF." For more information on intermittent diagnostic trouble codes, refer to Computer and Control Systems / Diagnosis By Symptom / Intermittents. Testing and Inspection

In situations where the EBCM detects more than one fault, only the fault with the lowest number DTC will be displayed. This DTC must be diagnosed and corrected before any higher number DTC can be displayed and diagnosed.