P2507
ECM/PCM Power Input Signal Low
The ECM/PCM switched-battery input reads below threshold while the ignition is on. Either the main relay does not close, the supply wire is broken or shorted to ground, or the battery is too low. Engine usually fails to start until the input recovers.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Main relay does not pull inCommon
- Open supply wirePossible
- Severely discharged batteryPossible
Parts involved
- Main Relay
- Power Input Wire
- Battery
P2507 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.