P257B – Vacuum Reservoir Control Circuit Low

P257B Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P257B Possible Causes

Faulty Vacuum Reservoir Control,Vacuum Reservoir Control harness is open or shorted,Vacuum Reservoir Control circuit poor electrical connection

P257B Description

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 out of factory specifications.