Diagnostic Aids

DO NOT enter this test sequence until a Code 111 (pass code) has been retrieved in KOEO SELF-TEST. If system has not passed KOEO SELF-TEST, codes recorded in KOER SELF-TEST may not be valid.

Deactivate self-test by removing and reconnecting jumper wire or by procedure specified by test equipment in use. Start engine, and run it for 2 minutes at 2000 RPM to warm Heated Exhaust Gas Oxygen Sensor (HO2S). Turn engine off, and wait 10 seconds. Activate KOER SELF-TEST using a jumper wire or appropriate procedure for test equipment used. Start engine. Record all diagnostic trouble codes displayed. Check following items:

• If Code 998 is displayed, EEC-IV system is operating in Failure Management Effects Mode (FMEM) and vehicle has not passed KOEO SELF-TEST. Vehicle cannot be diagnosed while in FMEM mode.
• If vehicle is equipped with a Brake On-Off (BOO) switch, brake pedal must be depressed and released after ID code portion of test.
• On vehicles with Power Steering Pressure (PSP) switch, turn steering wheel at least 1/2 turn and release within 1-2 seconds after ID code portion of test.
• If Dynamic Response Code appears, perform a brief Wide Open Throttle (WOT). DO NOT perform WOT unless requested.
• If a Code 111 (pass code) is retrieved during KOER SELF-TEST, service Continuous Memory Codes retrieved in KOEO SELF-TEST. See DIAGNOSTIC TROUBLE CODE REFERENCE CHART  .
• If KOER codes are present, see DIAGNOSTIC TROUBLE CODE REFERENCE CHART. If system will not output codes, go to CIRCUIT TEST QA.
• If a Code 111 (pass code) is retrieved during Continuous Memory Code portion of KOEO SELF-TEST and no driveability problem exists, EEC-IV testing is complete. If driveability problems are still present, go to TESTS W/O CODES (EEC -IV) - article in the ENGINE PERFORMANCE section.
• If a Code 111 (pass code) is retrieved during KOER SELF-TEST and intermittent fault(s) continue, go to CONTINUOUS MONITOR MODE (WIGGLE TEST) below.