Clearing Trouble Codes

NOTE: To prevent Engine Control Module (ECM) damage, key must be OFF when disconnecting or reconnecting power to ECM.

When ECM sets a Diagnostic Trouble Code (DTC), Malfunction Indicator Lamp (MIL) lamp will be turned on only for type "A" and "B", but a DTC will be stored in ECM's memory for all types of DTC. If problem is intermittent, MIL will go out after 10 seconds if fault is no longer present. The DTC will stay in ECM's memory until cleared by scan tool. Removing battery voltage for 10 seconds will clear some stored DTC's.

DTCs should be cleared after repairs have been completed. Some diagnostic tables will tell you to clear codes before using chart. This allows ECM to set DTC while going through chart, which will help to find cause of problem more quickly.