Key On, Engine Running (KOER) Test
- Verify that engine is at normal operating temperature. Run engine at 2000 RPM for 2 minutes, turn key off and immediately restart engine. Observe voltmeter and vacuum gauge for initialization pulses after restarting engine. The throttle kicker should also come on at this time and remain on throughout test.
- Check to see if engine has knock sensor. If so, have steel bar (socket extension) and tap hammer ready. As soon as initialization pulses appear, hold steel bar against manifold near knock sensor and tap bar lightly with hammer for 15 seconds (on models with knock sensor only).NOTE: If more than 4 pulses appear, check for open circuit between coil and pin 8 of MCU module connector.
- Observe and record service codes. When codes are complete, throttle kicker will retract. Stop engine and reconnect PCV valve. Perform tests for codes in the order that codes were displayed.
NOTE:
A service code 11 may be considered a failure and code 62 may be considered a pass (MCU okay) on vehicles equipped with an altitude switch operating above 4000 ft. or vehicles without an altitude switch that have MCU pin 6 grounded to the engine.
NOTE:
When code 11 is displayed for vehicles with a drive complaint of detonation (at WOT only) and/or poor performance, and vehicle is equipped with a universal ignition module, perform Spark Knock Test. On all other vehicles, testing is complete and MCU is functioning.