FixVault

Clearing Codes & Information Flags

When a code or flag is set, PCM stores code or flag in 2 different tables: general information and malfunction history. Codes and flags stored in malfunction history can only be cleared using scan tester. To clear codes and flags stored in general information, use scan tester, or turn ignition on and connect a jumper wire between ALDL connector terminals "A" and "B" three times within 5 seconds. See Fig 1.

NOTE: Codes and flags that are stored in general information are automatically cleared after 50 ignition cycles, or if power is disconnected from PCM.
Fig 1: Identifying ALDL Connector Terminals
G92J05262Courtesy of GENERAL MOTORS CORP.