P257B Possible Causes
- Faulty vacuum tank control
- Vacuum tank control harness is open or shorted
- Poor electrical connection in vacuum tank control circuit
How to Fix Code P257B
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 check engine light (or service engine soon warning light)
P257B Meaning
The Engine Control Module (ECM) monitors the vacuum tank control circuit signal. The ECM sets the OBDII code when the vacuum tank control circuit signal is outside factory specifications.