LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 1994 >> Forward Control 6.5 Y, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 6.5L Diesel >> Self-Diagnostic System >> Clearing Trouble Codes

Clearing Trouble Codes

CAUTION: When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION section before disconnecting battery.
NOTE: To prevent PCM damage, ensure ignition switch is in OFF position when disconnecting or reconnecting power to PCM.

Trouble codes should be cleared after repairs have been completed. Also, some diagnostic charts require codes to be cleared before using diagnostic chart.

  1. To clear codes, with ignition off, connect a jumper wire between Data Link Connector (DLC) terminal "B" (diagnostic terminal) and terminal "A" (ground). See Figure. Turn ignition on. Fully apply brake pedal, then fully apply accelerator pedal.
  2. Check MIL for DTC 12. Release brake pedal, then release accelerator pedal. Check MIL again for DTC 12. Remove jumper wire from DLC. Turn ignition off. If no hard fault codes are present (only intermittent codes exist), proceed to TESTS W/O CODES - 6.5L DIESEL article in this section for intermittent diagnostic procedures.
scientia non olet · About LEMON Manuals