LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 1988 >> Bronco II 4WD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> EEC-IV CEC System >> Quick Test >> Key On Engine Running (KOER) Self-Test >> Test Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Test Procedure

  1. Deactivate SELF-TEST (disconnect jumper wire). Start engine and run it at 2000 RPM for 2 minutes to warm up HEGO sensor. Turn engine off and wait 10 seconds.
  2. Start engine. Insert jumper to activate SELF-TEST. The engine ID code will be displayed. On vehicles equipped with Brake On/Off switch (BOO) the brake pedal MUST be depressed and released AFTER the ID code (within 1-2 seconds). On vehicles equipped with Power Steering Pressure Switch, the steering wheel MUST be turned one-half turn and released AFTER the ID code.
  3. If a Dynamic Response code occurs, briefly depress accelerator pedal to wide open throttle (WOT). A Dynamic Response code is a code 1 or 10 displayed after the Engine ID code and before the Engine Running codes. DO NOT  depress throttle during test unless a Dynamic Response code occurs. The ENGINE RUNNING SELF-TEST service codes will then be displayed. Observe and record all codes.
scientia non olet · About LEMON Manuals