Clearing Continuous Memory Codes
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 1988 Ford Ranger, 1988 Ford RV Cutaway, 1988 Ford Pickup, 1988 Ford F-Super Duty, and 1988 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
Perform KEY ON/ENGINE OFF (KOEO) SELF-TEST . When the first service code appears, exit SELF-TEST by disconnecting diagnostic tester or by removing jumper wire from Self-Test Input (STI) pigtail. Exiting QUICK TEST in this manner will clear all codes stored in continuous memory.