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Home >> Ford >> 2021 >> F-150 Police Responder >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Diagnostic Methods (Diesel) >> Quick Test Description >> Key ON Engine OFF (KOEO) Self-Test
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Key ON Engine OFF (KOEO) Self-Test

The KOEO self-test is a functional test of the PCM carried out with the ignition ON and the engine OFF. This test checks that all inputs and outputs (circuits, sensors, regulators, relays, and solenoids) connected to the PCM are electrically operating without a concern.