General Motors 8.1 — Clearing Diagnostic Trouble Codes - Non Scan
Testing & diagnosis · ECM diagnostic system
For the General Motors 8.1, from the General Motors service manual.
Applies to: General Motors 8.1L engine
Before you start
- The ignition must be cycled to OFF after codes are cleared or the DTCs will not clear.
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 DTCs are still present, repeat the DTC clearing procedure.
- If new DTCs are displayed, perform the 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.