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Home >> Ford >> 2004 >> Excursion 6.8 S, 4WD >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Controls - Powertrain DTC Charts & Descriptions - CNG, Flex-Fuel & Gasoline >> Diagnostic Trouble Code (DTC) Charts >> P1129 - Downstream Oxygen Sensors Swapped From Bank To Bank (Ho2S-12-22)

P1129 - Downstream Oxygen Sensors Swapped From Bank To Bank (Ho2S-12-22)

P1129 - DOWNSTREAM OXYGEN SENSORS SWAPPED FROM BANK TO BANK (HO2S-12-22)

Description:  The heated oxygen sensor (HO2S) monitor determines if the HO2S signal response for a fuel shift corresponds to the correct engine bank. The test fails when a response from the HO2S being tested is not indicated.
Possible Causes: 
  • Crossed HO2S harness connectors (downstream).
  • Crossed HO2S wiring at the harness connectors (downstream).
  • Crossed HO2S wiring at the 104-pin harness connectors (downstream).
Diagnostic Aids:  -
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
Gasoline - GO to H: Fuel Control STEP H69 -
Dedicated NGV GO to HA: Natural Gas Fuel Control STEP HA52 GO to HA: Natural Gas Fuel Control STEP HA52 GO to HA: Natural Gas Fuel Control STEP HA52