P1128

BAT Team

By BAT Team (Contact Me)
Last Updated 2017-01-17
A site with free advice from mechanics.

Trouble CodeFault LocationProbable Cause
P1128 Manifold Absolute Pressure Sensor Signal Lower Than Expected (ACURA, HONDA)
Long Term Fuel Trim B1 System Too Lean (AUDI, VOLKSWAGEN)
Closed Loop Fueling Not Achieved Bank 1 (CHRYSLER, DODGE, JEEP, MITSUBISHI)
Front O2 Sensor Connectors Swapped (FORD, LINCOLN, MERCURY)
Fuel System Lean Part Load (HYUNDAI)
Throttle Control Motor Circuit Short (INFINITI, NISSAN)
MAP Sensor Voltage Lower Than Expected (ISUZU)
Throttle Control Motor Lock Malfunction (LEXUS, TOYOTA)
HO2S Heater O2 Sensor Too Cool Before KOER Test (MAZDA)

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Other Manufacturer Specific Definitions for P1128

Front O2 Sensor Connectors Swapped (Ford)
Throttle actuator control (TAC) lock - malfunction (Toyota)
Long term fuel trim, system too lean (Volkswagen)
Manifold absolute pressure (MAP) sensor - pressure lower than expected (Acura)
Long term fuel trim, entire speed/load range, Bank 1 - system too lean (Audi)
Closed loop fuel control not achieved -bank 1 (Chrysler)
Heated oxygen sensor (H02S) 1, bank 1 signal error (Dodge)
MAP sensor – signal lower than expected (Honda)
Long term fuel trim – system too lean (Hyundai)
Throttle motor – short circuit (Infiniti)
Manifold absolute pressure (MAP) sensor - pressure lower than expected (Isuzu)
Closed loop fuel control not achieved -bank 1 (Jeep)
Heated oxygen sensor (H02S), upstream – transposed (Land Rover)
Throttle actuator control (TAC) lock- malfunction (Lexus)
Heated oxygen sensor (H02S) 1, bank 11 bank 2 -interchanged (Lincoln)
Heated oxygen sensor (H02S) -front – bank 1/bank 2 sensors transposed (Mazda)
Heated oxygen sensor (H02S) 1, bank 1/ bank 2 interchanged (Mercury)
Closed Loop Fueling Not Achieved Bank 1 (Mitsubishi)
Throttle valve position motor – short circuit (Nissan)
Manifold absolute pressure (MAP) sensor signallow (Saturn)

BAT Team Discussions for P1128

  • 2000 VW Cabrio Code P1128
    2000 VW Cabrio/100,000mi/4cyl I recieved a rejected inspection sticker because my car would not pass emissions. I went to autozone and had them check for codes and P1128 Fuel Air metering came up. I replaced the vacuum hoses I knew of as well as the rubber hose coming off of the valve cover, which...
  • 2001 Wolfsburg Jetta Gas Motor Fuel Pressure Monitor Sensor
    The code read when the fuel pressure monitor was replaced was PO172. The 2nd and 3rd time the check engine light came on was code P1128. Any help, anyone? Thanks, Nick...