General Motors — Clearing Diagnostic Trouble Codes - Non Scan
Testing & diagnosis · ECM / Diagnostic System
From a General Motors service manual — check it applies to your exact model before use.
Before you start
- If the DTC tool is not switched back to normal mode, the engine may not start and run
Procedure
- Install Diagnostic Trouble Code (DTC) tool
- Ignition ON, engine OFF
- Switch DTC tool to service mode or ON
- Move the throttle from 0% (idle) to 100% (WOT) and back to 0%
- Switch DTC tool to normal mode or OFF
- Turn ignition OFF for at least 20 seconds
- Ignition ON, engine OFF
- Switch DTC tool to service mode or ON and verify DTC 12 only; remove DTC tool
- If original DTC's are still present, repeat the DTC clearing procedure
- If new DTC's are displayed, perform the On-Board Diagnostic (OBD) system check
Tools required
- Diagnostic Trouble Code (DTC) tool Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Source: General Motors service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.