Engine-CodesGMC – P0123 GMC

P0123 GMC Code - Throttle Position Sensor Circuit High Voltage

Quick Answer

The P0123 diagnostic trouble code (DTC) for GMC vehicles refers to the Throttle Position Sensor Circuit High Voltage. Common causes include Faulty throttle position sensor, Damaged wiring or connectors in the sensor circuit, Corrosion or poor connections in the sensor circuit. 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
P0123 GMC indicates Throttle Position Sensor Circuit High Voltage.
Common causes
Common causes include Faulty throttle position sensor, Damaged wiring or connectors in the sensor circuit, Corrosion or poor connections in the sensor circuit.
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.
Table of contents Created and updated by William Orellana on Sep 08, 2024
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Code P0123 GMC Description

The P0123 diagnostic trouble code (DTC) for GMC vehicles refers to the Throttle Position Sensor Circuit High Voltage. This code indicates that the throttle position sensor is sending a higher voltage signal than what is expected by the engine control module (ECM). The throttle position sensor is a crucial component in the engine management system, as it helps determine the amount of air entering the engine, which in turn affects fuel delivery and ignition timing.

OBDII Code P0123 GMC - Throttle Position Sensor Circuit High Voltage
P0123 GMC Code - Throttle Position Sensor Circuit High Voltage

Common Causes of P0123 GMC

  1. Faulty throttle position sensor
  2. Damaged wiring or connectors in the sensor circuit
  3. Corrosion or poor connections in the sensor circuit
  4. Malfunctioning ECM
  5. Mechanical issues affecting the throttle body

Symptoms of P0123 GMC

  1. Check engine light illuminated on the dashboard
  2. Rough idling or engine misfires
  3. Hesitation or lack of response during acceleration
  4. Reduced fuel efficiency
  5. Engine stalling or rough running

How to Fix P0123 GMC

  1. Begin by confirming the P0123 code with a diagnostic scan tool to ensure it is indeed related to the throttle position sensor circuit high voltage.
  2. Inspect the throttle position sensor, wiring, and connectors for any visible damage or corrosion. Replace any damaged components.
  3. Test the throttle position sensor using a multimeter to verify proper voltage output. Replace the sensor if it is out of specification.
  4. Clear the DTC and reset the ECM to see if the code returns. Test drive the vehicle to ensure the issue has been resolved.
  5. If the problem persists, consult a professional mechanic to perform further diagnostics, such as checking the throttle body and ECM for any issues.

Cost to Fix P0123 GMC

The cost estimate for resolving a P0123 code related to the throttle position sensor circuit high voltage can vary depending on the specific cause of the issue. In general, the replacement of a throttle position sensor can range from $50 to $200, depending on the vehicle make and model. Labor costs for this repair can range from $80 to $150 per hour, with the total repair cost typically falling between $150 to $400. Additional costs may apply if other components need to be replaced or if further diagnostics are required. It is recommended to consult with a professional mechanic for an accurate cost estimate based on the specific circumstances of your vehicle.

Tech Notes for P0123 GMC





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Information for Specific GMC Models

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 P0123 GMC Code

1. What are the common symptoms of OBDII code P0123 in a GMC related to the throttle position sensor?

When the throttle position sensor circuit shows high voltage, you may experience issues like poor fuel economy, rough idling, stalling, or a lack of response from the accelerator pedal.

2. What are the typical causes of OBDII code P0123 in a GMC?

The throttle position sensor circuit high voltage code P0123 in a GMC is often caused by a faulty throttle position sensor, damaged wiring or connectors, or issues with the engine control module.

3. How can I diagnose the throttle position sensor in my GMC if I suspect it is causing OBDII code P0123?

To diagnose the throttle position sensor, you can use a multimeter to test its voltage output, check for any signs of physical damage, and inspect the wiring and connectors for any corrosion or loose connections.

4. Can a dirty throttle body or air filter cause OBDII code P0123 in a GMC?

Yes, a dirty throttle body or clogged air filter can disrupt the proper functioning of the throttle position sensor, leading to erroneous high voltage readings and triggering code P0123.

5. What are some repair tips for resolving OBDII code P0123 related to the throttle position sensor in a GMC?

When dealing with code P0123, start by inspecting and cleaning the throttle body, checking for any loose connections or damaged wiring, and if needed, replacing the throttle position sensor.

6. Is it safe to continue driving my GMC with OBDII code P0123 related to the throttle position sensor circuit high voltage?

It is not recommended to drive your GMC with OBDII code P0123, as it can lead to poor engine performance, reduced fuel efficiency, and potential safety hazards. It's best to address the issue promptly.

7. Can resetting the OBDII code P0123 in my GMC temporarily fix the issue with the throttle position sensor?

Resetting the OBDII code P0123 may temporarily clear the error code, but if the underlying issue with the throttle position sensor circuit high voltage is not addressed, the code is likely to reappear.

8. How much does it typically cost to repair OBDII code P0123 related to the throttle position sensor in a GMC?

The cost of repairing OBDII code P0123 in a GMC can vary depending on the cause of the issue. Replacing a faulty throttle position sensor may cost around $100 to $200, while addressing wiring or connector problems could be more expensive.

9. Can a DIY enthusiast with basic car repair skills fix OBDII code P0123 related to the throttle position sensor in a GMC?

Yes, if you have basic car repair skills and the necessary tools, you may be able to replace the throttle position sensor or address wiring issues causing OBDII code P0123 in your GMC. However, if you are unsure, it's best to consult a professional mechanic.

10. How can regular maintenance help prevent OBDII code P0123 related to the throttle position sensor in a GMC?

Regularly inspecting and cleaning the throttle body, ensuring the air filter is clean, and checking for any signs of wear or damage in the throttle position sensor circuit can help prevent issues that lead to code P0123 in your GMC.

Discuss the causes and fixes for P0123 GMC OBDII Code

  • Is it possible that the codes are link to the recall from GM with engine coolant and fire risk because my car has been part of the recall for as long as my car as been made 02 Buick regal saftey recall my car was "fixed from my. Dealership " but my car beauty cover caught on fire which should have been removed and they will not help me now my car reading both codes p0123. P0306

  • Unfortunately, as far as I know, neither of the codes are related to the recall you mention.