P0991

2017-10-10

Description:

  • The fault code P0991 indicates an intermittent issue in the circuit of the transmission fluid pressure sensor/switch 'E'. This sensor/switch is responsible for monitoring the fluid pressure within the transmission. An intermittent circuit issue suggests that there are sporadic disruptions in the electrical signal or connection.

Possible Symptoms:

  • Intermittent illumination of the Malfunction Indicator Lamp (MIL) or Check Engine Light.

  • Occasional abnormal transmission shifting behavior.

  • Intermittent harsh or delayed shifting between gears.

  • Erratic or unpredictable gear changes at times.

  • Momentary reduction in performance or power from the transmission.

  • Other associated transmission

  • related fault codes may be present intermittently.

  • No consistent or noticeable drivability issues are typically associated with this fault code.

Possible Causes:

  • Intermittent wiring or electrical connection issues in the circuit

  • Loose or corroded connectors or terminals

  • Faulty transmission fluid pressure sensor/switch 'E'

  • Vibrations or physical damage affecting the circuit

  • Intermittent fault in the transmission control module (TCM)

Related Parts:

  • Hydraulic Pressure Sensor: Hydraulic oil is needed for the gear lubrication system. This sensor measures oil pressure. This car's sensor has a problem which may cause difficulty in shifting gears

Possible Solutions:

  • Inspect the wiring and electrical connections in the circuit for any signs of damage, looseness, or corrosion. Ensure all connectors and terminals are securely connected.

  • Repair or replace any damaged or faulty wiring, connectors, or terminals as necessary.

  • Test and replace the transmission fluid pressure sensor/switch 'E' if it is determined to be faulty.

  • Address any vibrations or physical damage that may be affecting the circuit.

  • Perform diagnostic tests on the transmission control module (TCM) to identify any intermittent faults and repair or replace as necessary.

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