P257C Fault Code

Vacuum Reservoir Control Circuit High

• What does that mean?
• Symptoms
• Causes
• Solutions

The P257C fault code refers to an issue with the Vacuum Reservoir Control Circuit being detected as high. This code indicates that the voltage within the vacuum reservoir control circuit is above the acceptable range, potentially leading to improper operation of various systems relying on vacuum pressure.

What are the symptoms of the P257C code?

• Check Engine Light (CEL) illuminated
• Decreased engine performance
• Increased fuel consumption
• Difficulty in maintaining a stable idle
• Possible issues with brake boosting or HVAC controls

What causes the P257C code?

• Faulty vacuum reservoir
• Damaged or corroded wiring in the control circuit
• Malfunctioning vacuum control solenoid
• Faulty engine control module (ECM)
• Vacuum leaks in the system
• Poor electrical connection or grounding issues

How to fix P257C?

• Inspect and repair any damaged wiring or connectors.
• Test and replace the vacuum control solenoid if found faulty.
• Check the vacuum reservoir for leaks and ensure it operates within specifications.
• Use a scan tool to clear the fault code and test drive the vehicle to verify repairs.
• If necessary, replace the engine control module after ensuring other components are functioning properly.