LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1999 >> Forward Control 7.4 B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls Tests W/Codes - Diesel >> Self-Diagnostic System >> Retrieving DTCS
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Retrieving DTCS

DTCs are retrieved using a Tech 1 or 2 scan tool, or other OBD-II compatible scan tool connected to OBD-II 16-pin Data Link Connector (DLC). See Fig 1. DLC is located below instrument panel, on driver's side of vehicle.

Fig 1: Identifying OBD-II Data Link Connector (DLC)
G95D35181Courtesy of GENERAL MOTORS CORP.