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P0120 Mazda Code - Throttle Position Sensor Signal Out of Range

Quick Answer

The P0120 diagnostic trouble code (DTC) for Mazda vehicles indicates that the throttle position sensor (TPS) signal is out of range. Common causes include Faulty Throttle Position Sensor: The TPS itself may be malfunctioning, providing inaccurate signals to the ECM, Wiring or Connector Issues: Damaged or corroded wiring, connectors, or terminals in the TPS circuit can disrupt the signal transmission, Dirty Throttle Body: A buildup of carbon deposits or debris in the throttle body can affect the TPS operation. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P0120 Mazda indicates Throttle Position Sensor Signal Out of Range.
Common causes
Common causes include Faulty Throttle Position Sensor: The TPS itself may be malfunctioning, providing inaccurate signals to the ECM, Wiring or Connector Issues: Damaged or corroded wiring, connectors, or terminals in the TPS circuit can disrupt the signal transmission, Dirty Throttle Body: A buildup of carbon deposits or debris in the throttle body can affect the TPS operation.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0120 Mazda Description

The P0120 diagnostic trouble code (DTC) for Mazda vehicles indicates that the throttle position sensor (TPS) signal is out of range. The TPS is a crucial component of the electronic throttle control system, responsible for monitoring the position of the throttle pedal and sending this information to the engine control module (ECM). When the ECM detects that the TPS signal is not within the expected range, it triggers the P0120 code and illuminates the check engine light on the dashboard.

OBDII Code P0120 Mazda - Throttle Position Sensor Signal Out of Range
P0120 Mazda Code - Throttle Position Sensor Signal Out of Range

Common Causes of P0120 Mazda

  1. Faulty Throttle Position Sensor: The TPS itself may be malfunctioning, providing inaccurate signals to the ECM.
  2. Wiring or Connector Issues: Damaged or corroded wiring, connectors, or terminals in the TPS circuit can disrupt the signal transmission.
  3. Dirty Throttle Body: A buildup of carbon deposits or debris in the throttle body can affect the TPS operation.
  4. ECM Malfunction: A faulty engine control module (ECM) can also result in the P0120 code by not processing the TPS signal correctly.
  5. Mechanical Issues: Other mechanical problems such as a sticking throttle linkage or a vacuum leak can also trigger the P0120 code.

Symptoms of P0120 Mazda

  1. Check Engine Light: The most common symptom associated with the P0120 code is the illumination of the check engine light on the dashboard.
  2. Rough Idling: The vehicle may experience rough idling or fluctuations in engine speed when at a standstill.
  3. Hesitation or Stalling: The engine may hesitate or stall when accelerating or decelerating, especially at low speeds.
  4. Poor Acceleration: The vehicle may exhibit sluggish acceleration or a lack of power when driving.
  5. Reduced Fuel Efficiency: A faulty TPS signal can lead to decreased fuel efficiency, causing the vehicle to consume more fuel than usual.

How to Fix P0120 Mazda

  1. Diagnose the Issue: Use a diagnostic scan tool to retrieve the specific trouble code and perform a thorough inspection of the TPS, wiring, and connectors.
  2. Replace the Throttle Position Sensor: If the TPS is found to be faulty, replace it with a new one following the manufacturer's recommendations.
  3. Clean the Throttle Body: Remove any carbon deposits or debris from the throttle body to ensure smooth operation of the TPS.
  4. Repair Wiring or Connector Issues: Repair or replace damaged wiring, connectors, or terminals in the TPS circuit to restore proper signal transmission.
  5. Reset the ECM: Clear the trouble code from the ECM's memory and reset the adaptive learning values to ensure the new TPS is properly calibrated.

Cost to Fix P0120 Mazda

The typical repair costs for addressing the P0120 code in a Mazda vehicle can range from $100 to $300, including parts and labor. However, the actual cost may vary depending on the specific make and model of the vehicle, the location of the repair shop, and the extent of the repairs needed. It is recommended to obtain a detailed estimate from a trusted auto repair shop to determine the precise cost based on your vehicle's requirements. Keep in mind that diagnostic time and labor rates can influence the final cost, with rates typically ranging between $80 and $150 per hour at most auto repair facilities.

When is the Code Detected?

Malfunction is detected when an excessively low or high voltage from the sensor is sent to ECM.

Need more information about the P0120 Mazda code?

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Need Help with the Code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0120 Mazda Code

1. What are the common symptoms of OBDII code P0120 in a Mazda related to the throttle position sensor?

The common symptoms include poor acceleration, rough idling, stalling, and potential issues with shifting gears.

2. What are the possible causes of the P0120 code in a Mazda, indicating a throttle position sensor signal out of range?

The causes can vary but may include a faulty throttle position sensor, damaged wiring or connectors, or issues with the throttle body itself.

3. How can I diagnose the P0120 code in my Mazda related to the throttle position sensor?

You can use an OBDII scanner to read the code and perform a visual inspection of the sensor, wiring, and connectors. Testing the sensor's voltage output may also be necessary.

4. Can I drive my Mazda with the P0120 code indicating a throttle position sensor issue?

It is not recommended to drive your Mazda with this code, as it can lead to poor performance and potential safety hazards. It's best to address the issue promptly.

5. What are some repair tips for fixing the P0120 code in a Mazda?

Start by checking and cleaning the throttle body, inspecting the sensor and its connections, and replacing the throttle position sensor if necessary to resolve the issue.

6. Is it possible to reset the P0120 code in a Mazda without fixing the underlying issue?

While you can clear the code using an OBDII scanner, it is crucial to address the root cause of the problem to prevent it from recurring.

7. How much does it typically cost to repair the P0120 code related to the throttle position sensor in a Mazda?

The cost can vary depending on the exact cause of the issue, but it may involve replacing the throttle position sensor, which can range from $100 to $300 including parts and labor.

8. Can a DIY enthusiast with basic mechanical skills fix the P0120 code in a Mazda themselves?

If you have the necessary tools and knowledge, you may be able to replace the throttle position sensor yourself. However, if you're unsure, it's best to consult a professional mechanic.

9. Are there any preventive measures to avoid the recurrence of the P0120 code in a Mazda after repair?

Regularly inspecting and cleaning the throttle body, checking the sensor connections, and ensuring proper maintenance of the throttle system can help prevent the code from reappearing.

10. How urgent is it to address the P0120 code in a Mazda once it appears?

It is recommended to address the issue promptly to prevent further damage to the engine and ensure optimal performance of your Mazda.

Discuss the causes and fixes for P0120 Mazda OBDII Code

Submit a New Comment

  • I took the TPS sensor off to gain better access to behind the engine. Unknowingly, I reinstalled it without the knowledge that it needed to be installed a certain way with the spring loading. Long story short, the engine light went on and now I am trying to reinstall it the right way but cannot seem to do so to where the idle rests where it should. I am looking for tips to how to install it properly and what I should be considering when doing so. The car is a 98 Protege.

    Reply to Comment

  • Try loosing the screws and moving the TPS until the idle start changing.

    Here is the information from the service manual to test the sensor which could be used to adjust the sensor:

    1. Detach the connector from the throttle position sensor.
    2. Connect an ohmmeter between terminals IDL and E.
    3. Insert a 0.004 in. (0.1mm) feeler gauge between the throttle stop screw and
    stop lever.
    4. Verify there is continuity between terminals IDL and E.
    5. Insert a 0.024 in. (0.6mm) feeler gauge between the throttle stop screw and
    stop lever.
    6. Verify there is continuity no between terminals IDL and E.
    7. Connect an ohmmeter to the throttle sensor terminals Vt and E.
    8. Verify that resistance increases as throttle valve opening increase.
    9. With throttle valve fully closed the resistance should be below 1 kilohm and
    as throttle valve is fully opened resistance should increase to approximately 5
    kohms.

    Reply to Comment