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Engine-Codes – Generic – P1123

P1123 Code - Throttle Position Sensor Circuit Intermittent High Voltage

Quick Answer

The P1123 diagnostic trouble code indicates that there is an intermittent high voltage in the throttle position sensor circuit. Common causes include Faulty Throttle Position Sensor: The TPS itself may be malfunctioning, causing high voltage readings in the circuit, Wiring Issues: Damaged or corroded wiring in the TPS circuit can lead to intermittent high voltage, Poor Electrical Connections: Loose or poor electrical connections at the TPS or ECM can also trigger this code. 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
P1123 indicates Throttle Position Sensor Circuit Intermittent High Voltage.
Common causes
Common causes include Faulty Throttle Position Sensor: The TPS itself may be malfunctioning, causing high voltage readings in the circuit, Wiring Issues: Damaged or corroded wiring in the TPS circuit can lead to intermittent high voltage, Poor Electrical Connections: Loose or poor electrical connections at the TPS or ECM can also trigger this code.
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 06, 2024
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Code P1123 Description

The P1123 diagnostic trouble code indicates that there is an intermittent high voltage in the throttle position sensor circuit. The throttle position sensor (TPS) is a crucial component of the vehicle's electronic fuel injection system, as it measures the position of the throttle plate and sends this information to the engine control module (ECM). A high voltage reading in the TPS circuit could lead to incorrect fuel delivery, affecting engine performance and fuel efficiency. If not addressed, this issue can potentially cause drivability problems, engine stalling, poor acceleration, and even increased emissions.

OBDII Code P1123 - Throttle Position Sensor Circuit Intermittent High Voltage
P1123 Code - Throttle Position Sensor Circuit Intermittent High Voltage

Common Causes of P1123

  1. Faulty Throttle Position Sensor: The TPS itself may be malfunctioning, causing high voltage readings in the circuit.
  2. Wiring Issues: Damaged or corroded wiring in the TPS circuit can lead to intermittent high voltage.
  3. Poor Electrical Connections: Loose or poor electrical connections at the TPS or ECM can also trigger this code.
  4. ECM Malfunction: A malfunctioning engine control module may incorrectly interpret the TPS signal, leading to high voltage readings.
  5. Environmental Factors: Extreme temperatures or moisture can affect the TPS circuit, causing intermittent high voltage readings.

Symptoms of P1123

  1. Check Engine Light: The most common symptom associated with this code is the illumination of the check engine light on the vehicle's dashboard.
  2. Engine Surging: The engine may surge or hesitate during acceleration due to incorrect throttle position readings.
  3. Rough Idle: The vehicle may experience a rough or unstable idle, potentially leading to vibrations or shaking.
  4. Reduced Fuel Efficiency: An intermittent high voltage in the TPS circuit can cause the engine to run rich or lean, resulting in decreased fuel efficiency.
  5. Difficulty Starting: In some cases, the vehicle may have difficulty starting or may require multiple attempts to start the engine.

How to Fix P1123

  1. Diagnose the Issue: Use a diagnostic scan tool to retrieve the trouble code and perform a thorough inspection of the TPS circuit.
  2. Check Wiring and Connections: Inspect the wiring harness for any damage, corrosion, or loose connections. Repair or replace as necessary.
  3. Test Throttle Position Sensor: Test the TPS for proper operation using a multimeter or scan tool. Replace the sensor if it is faulty.
  4. Clear Codes and Test Drive: Clear the trouble code from the ECM and test drive the vehicle to ensure that the issue has been resolved.
  5. Perform Relearn Procedure: In some cases, a relearn procedure may be required to recalibrate the TPS and ECM after repairs have been made.

Cost to Fix P1123

The typical repair costs for addressing a P1123 code can range from $100 to $300, depending on the specific cause of the issue and the cost of parts and labor. It's important to note that diagnostic time and labor rates can vary, so it's advisable to check with local auto repair shops for a more accurate estimate. Additionally, factors such as the vehicle make and model, engine type, and location can influence the overall repair costs.

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Code P1123 Information for Specific Makes

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 P1123 Code

1. What are the common symptoms of OBDII code P1123 (Throttle Position Sensor Circuit Intermittent High Voltage)?

The common symptoms include rough idling, stalling, poor acceleration, and potential issues with the vehicle's fuel efficiency.

2. What are the possible causes of OBDII code P1123?

The code P1123 can be caused by a faulty throttle position sensor, wiring issues in the throttle position sensor circuit, or problems with the engine control module.

3. How can I diagnose the cause of OBDII code P1123?

Diagnosing the cause of P1123 involves using a scan tool to check for the code, testing the throttle position sensor, inspecting the wiring for damage, and checking for any loose connections.

4. Can I drive my vehicle with OBDII code P1123?

It is not recommended to drive your vehicle with code P1123 present, as it can lead to further damage and potential safety hazards. It's best to address the issue promptly.

5. How do I repair OBDII code P1123?

Repairing code P1123 typically involves replacing the faulty throttle position sensor, repairing any damaged wiring, or reprogramming the engine control module if necessary.

6. Are there any DIY tips for fixing OBDII code P1123?

While some basic troubleshooting steps can be done by DIY enthusiasts, it is recommended to seek professional help for diagnosing and repairing OBDII code P1123 to ensure proper resolution.

7. How much does it cost to fix OBDII code P1123?

The cost of fixing code P1123 can vary depending on the extent of the issue, the need for parts replacement, and labor costs. It is advisable to get estimates from a trusted mechanic or repair shop.

8. Can a bad throttle position sensor cause code P1123?

Yes, a faulty throttle position sensor is a common cause of OBDII code P1123, as it can lead to intermittent high voltage readings in the sensor circuit.

9. Will resetting the OBDII system clear code P1123?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue causing P1123 is not addressed, the code is likely to reappear after driving the vehicle for a while.

10. How urgent is it to address OBDII code P1123?

It is recommended to address OBDII code P1123 as soon as possible to prevent potential damage to other engine components, ensure safe driving conditions, and maintain optimal vehicle performance.

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