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What does Error Code P0122 mean?

Moderate Issue
DTC Code P0122 indicates a Throttle Position Sensor 1 Circuit Low Voltage issue. This occurs when the Engine Control Module (ECM) detects that the throttle position sensor 1 signal voltage is below 0.32 V for more than 1 second, affecting the communication between the throttle body and ECM.

What are the symptoms of Error Code P0122?

  • Engine Light ON: The check engine light or service engine soon warning light illuminates, indicating a potential issue with the throttle position sensor circuit.
  • Poor Acceleration: The vehicle may experience sluggish or unresponsive acceleration due to incorrect throttle position readings.
  • Stalling or Rough Idle: The engine may stall or idle roughly as the throttle position sensor fails to provide accurate data to the engine control module.
  • Reduced Fuel Efficiency: Inaccurate throttle position readings can lead to improper air-fuel mixture, resulting in decreased fuel efficiency.

What causes Error Code P0122?

  • The throttle body assembly may be malfunctioning, leading to incorrect voltage readings from the throttle position sensor.
  • There could be an open or short in the throttle body assembly harness, disrupting the electrical signal.
  • Poor electrical connections in the throttle body assembly circuit can cause intermittent or low voltage signals.
  • The engine control module (ECM) might be faulty, affecting the sensor's ability to communicate accurate data.
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How to fix Error Code P0122?

  • Initial Inspection: Inspect the throttle position sensor (TPS) and its wiring for any visible damage or disconnection. Ensure the connectors are secure and free from corrosion.
  • Check Voltage Supply: Using a multimeter, measure the voltage at the TPS connector. The reference voltage should be around 5 volts. If the voltage is low, inspect the wiring and the power supply to the sensor.
  • Sensor Ground Verification: Verify the ground connection of the TPS. A poor ground can cause low voltage readings. Ensure the ground wire is intact and properly connected.
  • Signal Wire Testing: Test the signal wire from the TPS to the Engine Control Module (ECM) for continuity. A break in the wire can result in a low voltage signal.
  • Sensor Functionality Test: With the ignition on, manually move the throttle and observe the voltage change on the signal wire. The voltage should increase smoothly as the throttle opens.
  • ECM Evaluation: If all wiring and sensor tests are normal, evaluate the ECM for faults. A malfunctioning ECM can misinterpret sensor signals.
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