11. Carry Out The Key On Engine Running (KOER) On-Demand Self-Test
11. CARRY OUT THE KEY ON ENGINE RUNNING (KOER) ON-DEMAND SELF-TESTPurpose:
The purpose of this test is to determine if the PCM has detected any fault conditions that would cause a performance problem while the engine is running. The KOER self-test carries out step tests on the injection control pressure system and the exhaust back pressure system.
Step tests are PCM controlled tests where the PCM commands a specific exhaust back pressure or injection control pressure (ICP) and then measures the result. If a predetermined threshold is not reached, a DTC is generated. This test can be carried out at any engine temperature.
Carry Out The KOER On-Demand Self-Test
NOTE: Before carrying out the KOER On-Demand Self-Test make sure the high pressure oil passages are free of air. A recent repair to the system may allow air to enter the oil passages. To remove the air, drive the vehicle (with deceleration and acceleration cycles) at highway speeds for 32 km (20 miles).
- The self-test verifies the ICP, exhaust gas recirculation (EGR), and variable geometry turbo VGT) systems performance.
Recommended Procedure:
NOTE: The engine will run rough during this test.
Connect the scan tool. Turn off all accessories. If the vehicle is equipped with a power take-off (PTO) system or auxiliary idle control, it must be turned off to carry out the self-test.
- Carry out the necessary vehicle preparation and visual inspection. Refer to Diagnostic Methods, Vehicle Check/Preparation. Vehicle Check/Preparation
- Refer to the scan tool operating manual for instructions.
- Ignition ON, engine running.
- Follow the operating instructions from the diagnostic menu.
- Carry out a KOER On Demand Self-Test.
- Record the DTCs and refer to the appropriate pinpoint test.
Tools Required:
Scan tool