Powertrain

P1129 - FAULT CODE - OBD2

Table Of Contents

    Description of DTC code P1129 Generic

    The MAP (Manifold Absolute Pressure) Sensor monitors the intake manifold pressure. Then, it provides this data to the PCM (Powertrain Control Module) that uses it to calculate air density; a value used to determine the engine’s air/mass flow rate. The fuel dosage can also be calculated with the information sent by the MAP Sensor to optimize the combustion process.

    The signal from the Manifold Absolute Pressure Sensor is compared by the PCM with other sensors signals and can be checked for proper operation. Keep in mind that the readings from this sensor should change with driving conditions.

    The PCM continuously checks the MAP Sensor. If voltages exceeding the maximum set limit are detected, the P1129 OBDII fault code will be stored.

    Symptoms of fault code P1129 Generic

    • The Check Engine light turns on.
    • Irregularities in idling.
    • The engine stops unexpectedly.

    Causes of OBD2 P1129 Generic

    The P1129 OBD2 diagnostic code P1129 is set for the following reasons:

    • The MAP Sensor vacuum hose may not be adjusted correctly.
    • The Absolute Pressure Manifold wiring or connector may be faulty.
    • The Manifold Absolute Pressure Sensor may be bad.

    Possible solutions of the DTC code P1129 Generic

    Steps to troubleshoot the P1129 OBDII DTC:

    • See Technical Service Bulletins.
    • Check the MAP Sensor vacuum hose connections for inconsistencies. Make adjustments if necessary.
    • Check the Manifold Absolute Pressure Sensor wiring for burn or wear damage. Repair if necessary.
    • Perform voltage and continuity tests on MAP Sensor Check for 5 volts at the sensor connector and a ground signal. If these values are within normal parameters for proper operation, suspect a faulty sensor.

     

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