Solution DTC P0120 TPS sensor

Solution DTC P0120 TPS sensor – In this discussion we focus on the problem of DTC P0120. All fault codes that occur in the engine are electrical. This code usually comes from a TPS sensor problem. Let’s see what actually happened to the error code.

Solution DTC P0120 TPS sensor

P0120 is a diagnostic trouble code (DTC) for Circuit Fault “TPS “A.” This can occur for a variety of reasons and mechanics will need to diagnose the specific cause for this code to trigger in your situation.

Code definition P0120

Throttle Pedal Position Sensor/Switch (TPS) Circuit “A” Fault

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Solution DTC P0120 TPS sensor
Throttle position sensor.

What does code P0120 mean?

P0120 is a generic OBD-II code indicating that the Engine Control Module (ECM) has seen the TPS A sensor circuit output voltage drop below or above the sensor’s expected range, or chatter when compared to the TPS B sensor circuit.

What causes code P0120?

The ECM detects that the output of the TPS A sensor circuit is out of the specified voltage range in relation to the TPS B sensor circuit.

The TPS A sensor circuit output drops below 2 volts or above 4.5 volts.

What are the symptoms of code P0120?

  • The ECM turns on the Check Engine Light and enters failsafe mode by cutting off current to the throttle actuator to place the throttle valve at an opening of less than 6 degrees.
  • The ECM controls fuel injection and timing to control engine speed.
  • The vehicle will be able to drive very slowly with a limited throttle response.
  • The engine may idle higher than normal, but will not accelerate properly.

Note: Symptoms are determined by the manufacturer’s failsafe ECM strategy for the vehicle during failure and may vary between manufacturer and vehicle.

How do mechanics diagnose code P0120

  • Scans and documents received code and views freeze frame data to see when code is set
  • Reset the code to clear the OBD-II error code and retest the vehicle to see if the code returns
  • Visually inspect all TPS connections and cables for any loose or damaged items.
  • Compares the data between the TPS of circuits A and B with the scanner, and if incorrect, replaces the TPS as directed by the appropriate test.

Common errors when diagnosing code P0120

  • First, not doing a visual inspection first
  • Not scanning, documenting, deleting, and retesting code to verify failure
  • Not replacing the TPS sensor when the test shows a problem
  • And, not comparing TPS A and B sensors to specifications before and after repair or replacement

How serious is code P0120?

Code P0120 will put the engine ECM into failsafe mode, which will cause various drive complaints until the repair is complete. For example, lack of acceleration, high idle, bucking or jerking, limited speed, and possible stalling depending on the manufacturer’s failsafe mode strategy.

What fix can fix code P0120?

  • Repair or replace the TPS connector
  • Repair cables as necessary
  • Replacing TPS with new sensors

Additional comments to consider regarding code P0120

  • Code P0120 may be accompanied by other TPS codes, so taking proper tests from the manufacturer for each code received may be necessary to remedy the complaint.
  • Most failures for code P0120 involve a faulty TPS sensor not tracking throttle angle properly.
  • All TPS-related codes will enable failsafe mode and cause the same drive symptoms.

1 thought on “Solution DTC P0120 TPS sensor

  1. Pingback: How to solve DTC P0123 - Throttle Position Sensor/Switch 'A' Circuit High Input | Hi-tech for Future

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