P257C Possible Causes
- Faulty vacuum reservoir control
- Vacuum reservoir control harness is open or shorted
- Poor electrical connection in vacuum reservoir control circuit
How to Fix Code P257C
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.
Possible Symptoms
Illuminated engine light (or service engine soon warning light)
P257C Meaning
The Engine Control Module (ECM) monitors the vacuum reservoir control circuit signal. The ECM sets the OBDII code when the vacuum reservoir control circuit signal is outside factory specifications.