LEMON Manuals: Even more car manuals for everyone
Home >> Ford >> 2009 >> Flex Limited, FWD >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Powertrain DTC Charts & Descriptions (Except Diesel & Hybrid) >> DTC Diagnosis >> DTC P2257: - Secondary Air Injection (Air) System Control A Circuit Low

DTC P2257: - Secondary Air Injection (Air) System Control A Circuit Low

DTC P2257: - SECONDARY AIR INJECTION (AIR) SYSTEM CONTROL A CIRCUIT LOW

Description:  The AIR system monitor circuit is low, indicating the secondary AIR pump is off although the secondary AIR pump was commanded on by the powertrain control module (PCM).
Possible Causes: 
  • Open B+ circuit
  • Open VPWR circuit
  • Open voltage circuit between the AIR relay and the secondary AIR pump
  • Damaged AIR relay
Diagnostic Aids:  The AIR monitor circuit PCM input contains a pull up voltage through a resistance internal to the PCM. This voltage is normally held low by the resistance path through the secondary AIR pump when the secondary AIR pump is off.
A single electrical open circuit component such as an AIR relay coil in this multi-component circuit is not detected by the PCM output driver, yet it sets DTC P2257.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to Pinpoint Test HM .