P1120 FORD – Throttle Position Sensor Out of Range

The P1120 code for a Ford vehicle is related to a problem with the throttle position sensor (TPS), which is responsible for detecting the position of the accelerator pedal. This sensor allows the ECM (engine control module) to regulate air intake and the air-fuel mixture based on the throttle position.

Meaning of the P1120 Code

The throttle position sensor (TPS) sends a signal to the engine control module (ECM) that is proportional to the throttle valve opening angle. This signal allows the ECM to determine various engine conditions, such as:

• Closed throttle: Idle or deceleration.

• Partial throttle: Cruise or moderate acceleration.

• Wide open throttle: Maximum acceleration.

The P1120 code is generated when the sensor voltage sent to the ECM falls outside the expected value ranges for the system. This can be due to a malfunction of the sensor itself or a problem in the sensor circuit.

Possible Causes of the P1120 Code

1. Faulty throttle position sensor: If the sensor is damaged or not functioning correctly, it may send incorrect signals to the ECM.

2. Open or shorted throttle position sensor harness: Faulty wiring or a broken connection can prevent the sensor from properly transmitting information to the ECM.

3. Poor electrical connection in the throttle position sensor circuit: Corroded, bent, or broken connector pins can cause a loss of signal.

4. Misadjusted throttle position sensor: A misaligned or improperly adjusted sensor can lead to incorrect signal readings, disrupting engine operation.

Possible Symptoms of the P1120 Code

• Engine light on (Check Engine Light or Service Engine Soon).

• No throttle response: The engine may not respond correctly to accelerator pedal commands, resulting in a loss of power.

• Sluggishness or reduced performance: A slow or imprecise throttle response can affect vehicle driving.

How to Fix the P1120 Code

1. Check the throttle position sensor (TPS):

   • Inspect the sensor for signs of failure (e.g., cracks or visible damage).

   • If the sensor is faulty, it will need to be replaced.

2. Inspect the wiring harness and connectors:

   • Visually check the wiring and connectors associated with the throttle position sensor for signs of damage (cut wires, corrosion, loose connectors).

   • If cables are damaged or corroded, repair or replace them.

3. Check the electrical connection:

   • Ensure the sensor connector pins are clean, not corroded, and properly connected.

   • Clean the connectors if necessary and reinsert them correctly.

4. Check the throttle position sensor alignment:

   • Ensure the sensor is properly aligned and correctly installed on the throttle shaft. If the sensor is misadjusted, adjust it or replace it if necessary.

5. Clear the code and test:

   • Once repairs have been made, clear the code using an OBDII scanner and perform a road test to check if the problem persists.

Conclusion

The P1120 code indicates a problem with the throttle position sensor (TPS) or its circuit. To resolve this issue, it is essential to check the condition of the sensor, wiring, and electrical connectors. If the sensor is faulty, it will need to be replaced. If the wiring is damaged, repairs will be necessary to restore proper system operation.