P2509
PowertrainPcm Powerhigh severityECM/PCM Power Input Signal Intermittent
What P2509 Means
The engine controller detected an intermittent loss of power at its main power input. This can cause the module to reset or lose data during operation.
Symptoms
- Intermittent stalling
- Check engine light on
- Random driveability issues
Common Causes
- Loose or corroded power connector
- Faulty ignition switch or relay
- Damaged wiring or poor ground
- Failing PCM
Diagnostic Steps
- Check battery and ground connections
- Inspect PCM power feed wiring and connectors
- Test power supply relay and ignition switch
- Wiggle-test harness while monitoring voltage
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