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2021 FORD MUSTANG MACH-E
Standard Range Dual Motor AWD•AWD•AUTOMATIC•ev
6 active safety recalls on this vehicle — view recalls
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Repairs0Labor316Torque3724Fluid5DTC769Battery1Maintenance0Recalls6
P1001low severityPowertrain

KOER Self-Test Not Able to Complete

on 2021 Ford Mustang Mach-E Standard Range Dual Motor AWD · AWD

What this code means

The Key On Engine Running (KOER) self-test was unable to complete. This indicates the PCM could not finish its powered-on engine running diagnostic routine, possibly due to another existing fault or test conditions not being met.

Symptoms

  • Check Engine Light
  • Self-test cannot complete
  • Other DTCs may be stored

Common causes

  • Existing DTCs preventing test completion
  • Engine not at operating temperature
  • Accessories not turned off during test
  • PCM malfunction

Diagnostic steps

  1. Ensure engine is fully warmed up before running KOER test
  2. Turn off all accessories (A/C, lights, radio)
  3. Check for and resolve any other stored DTCs first
  4. Retry KOER self-test

Repair notes

Resolve other DTCs first, then re-run KOER self-test with engine at operating temperature.

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