P0120 – OBD-II DTC

OBD-II DTC P0120 – Throttle Position Sensor/Switch A Circuit Malfunction

DTC P0120 meaning

DTC P0120 refers to a malfunction in the Throttle Position Sensor (TPS) or its circuit. The TPS is a critical component that monitors the position of the throttle plate in the engine’s intake system. This information is sent to the Engine Control Module (ECM) to adjust fuel delivery and ignition timing accordingly. When the ECM detects an issue with the TPS or its circuit, it triggers the P0120 code.

DTC P0120 symptoms

Common symptoms associated with DTC P0120 may include:

• Check Engine Light illuminated
• Unresponsive or erratic throttle response
• Engine stalling or hesitation during acceleration
• Reduced engine power or performance
• Increased fuel consumption

DTC P0120 causes

Several factors can lead to the P0120 code, including:

• Faulty Throttle Position Sensor
• Wiring issues such as shorts, opens, or corrosion in the TPS circuit
• Faulty Engine Control Module (ECM)
• Improperly adjusted throttle linkage
• Vacuum leaks affecting throttle operation

DTC P0120 seriousness

DTC P0120 can be considered serious as it affects the engine’s performance and drivability. If left unaddressed, it may lead to further engine damage or safety issues while driving. It is advisable to diagnose and repair the issue promptly to ensure safe vehicle operation.

How to diagnose DTC P0120

To diagnose DTC P0120, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the P0120 code.
2. Inspect the Throttle Position Sensor and its wiring for visible damage or corrosion.
3. Check the TPS voltage output using a multimeter while moving the throttle.
4. Verify the ground and power supply to the TPS.
5. Examine the Engine Control Module for any faults or updates.

How to fix DTC P0120 step-by-step instructions

To fix DTC P0120, follow these steps:

1. Disconnect the battery to ensure safety while working on the electrical system.
2. Inspect and repair any damaged wiring or connectors related to the TPS.
3. If the TPS is faulty, replace it with a new one.
4. Recheck the throttle linkage for proper adjustment and operation.
5. Reconnect the battery and clear the DTC using an OBD-II scanner.
6. Test drive the vehicle to ensure the issue is resolved and the Check Engine Light does not reappear.

How to erase DTC P0120

To erase DTC P0120, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the “Erase Codes” or “Clear DTCs” option on the scanner.
4. Confirm the action to clear the codes.
5. Disconnect the scanner and start the engine to verify that the Check Engine Light remains off.

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