AutoCodes – Subaru – P0123 Subaru

P0123 Subaru Code - Throttle Position Sensor/Switch 'A' Circuit High Input

Quick Answer

The Throttle Position Sensor (TPS) responds to the accelerator pedal movement. Common causes include Faulty throttle position sensor, Throttle position sensor harness is open or shorted, Throttle position sensor circuit poor electrical connection. 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 Subaru indicates Throttle Position Sensor/Switch 'A' Circuit High Input.
Common causes: Common causes include Faulty throttle position sensor, Throttle position sensor harness is open or shorted, Throttle position sensor circuit poor electrical connection.
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.

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Code Popularity 21,198

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0123 Subaru Description

The Throttle Position Sensor (TPS) responds to the accelerator pedal movement. This sensor is a kind of potentiometer which transforms the throttle position into output voltage, and emits the voltage signal to the Engine Control Module (ECM). In addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage signal to the ECM.
Idle position of the throttle valve is determined by the ECM receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the Wide open and closed throttle position switch, which is built into the throttle position sensor unit, is not used for engine control.

OBDII Code P0123 Subaru - Throttle Position Sensor/Switch 'A' Circuit High Input - AutoCodes.com — P0123 Subaru Code - Throttle Position Sensor/Switch 'A' Circuit High Input

What does this mean?

What are the Possible Causes of the DTC P0123 Subaru?

Faulty throttle position sensor
Throttle position sensor harness is open or shorted
Throttle position sensor circuit poor electrical connection

How to Fix the DTC P0123 Subaru?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0123 Subaru code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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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 P0123 Subaru Code

1. What are the common symptoms of OBDII code P0123 in a Subaru related to the throttle position sensor/switch 'A' circuit high input?

- Common symptoms include issues with acceleration, sudden changes in engine speed, poor fuel efficiency, and possible stalling or hesitation.

2. What are the primary causes of OBDII code P0123 in a Subaru?

- The main causes are typically a faulty throttle position sensor, damaged wiring or connectors in the sensor circuit, or issues with the engine control module (ECM).

3. How can I diagnose the throttle position sensor/switch 'A' circuit high input issue in my Subaru?

- You can diagnose the problem by using an OBDII scanner to retrieve the fault code, checking the throttle position sensor's voltage, inspecting the sensor's wiring and connectors for damage, and testing the ECM.

4. Can I drive my Subaru with OBDII code P0123 present?

- It is not recommended to drive your Subaru with this code present, as it can lead to performance issues and potentially cause further damage to the vehicle.

5. How can I repair OBDII code P0123 in my Subaru?

- Repair options include replacing the throttle position sensor, repairing or replacing damaged wiring or connectors, and resetting the ECM to clear the fault code.

6. Will resetting the ECM clear the OBDII code P0123 in my Subaru?

- Resetting the ECM may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear.

7. How much does it typically cost to repair OBDII code P0123 in a Subaru?

- The cost of repair can vary depending on the exact cause of the issue, but it may range from $100 to $300 for parts and labor.

8. Can a DIY enthusiast fix OBDII code P0123 in a Subaru?

- While some experienced DIY enthusiasts may be able to replace the throttle position sensor or repair wiring issues, it is recommended to consult a professional mechanic for accurate diagnosis and repair.

9. Are there any preventative measures to avoid OBDII code P0123 in a Subaru?

- Regular maintenance and inspections of the throttle position sensor, wiring, and connectors can help prevent issues that may trigger the code.

10. How long does it typically take to repair OBDII code P0123 in a Subaru?

- The repair time can vary depending on the exact cause of the issue and the availability of parts, but it may take anywhere from one to three hours to complete the repair.