What Does the P0123 Code Mean?
OBD-II Code P0123 is defined as a Throttle/Pedal Position Sensor/Switch “A” Circuit High Input. This code indicates that the engine control module (PCM) has detected a high voltage signal from the Throttle Position Sensor (TPS) or Pedal Position Sensor (PPS), which could suggest a malfunction in the sensor or its circuit.
What Causes the P0123 Code?
The P0123 code can be triggered by several issues, including:
- Defective Throttle or Pedal Position Sensor or Switch
- Dirty or carbon-filled Throttle Body
- Torn or jammed floor mats obstructing the accelerator pedal
- Chafed or corroded wiring or connections related to the Throttle/Pedal Position Sensor
What Are the Symptoms of the P0123 Code?
Common symptoms associated with the P0123 code include:
- Illuminated Check Engine Light
- Hard starting of the engine
- Engine hesitation during acceleration
- No noticeable symptoms in some cases
How Serious Is the P0123 Code?
The P0123 code is considered urgent. If not addressed, it can lead to significant performance issues, including limited vehicle speed (entering “Limp home mode”) to protect the engine and driver. Prompt diagnosis and repair are crucial to avoid further damage.
How to Diagnose the P0123 Code
To diagnose the P0123 code, follow these steps:
- Record freeze frame information when the code is set.
- Conduct a test drive to replicate the code-setting conditions, monitoring engine load, RPM, and road speed with a data streaming scan tool.
- Check the Throttle/Pedal Position Sensor connector for a steady 5-volt reference voltage and ensure a good ground.
- Test the Throttle/Pedal Position output from its signal wire, watching for voltage changes as you manually operate the throttle or pedal.
Common Repairs for the P0123 Code
Common repairs for the P0123 code include:
- Replacing defective Throttle or Pedal Position Sensors
- Cleansing the Throttle Body of carbon build-up
- Repairing or replacing chafed or corroded wiring and connectors
- Removing any obstructions such as torn or jammed floor mats
How Much Does It Cost to Fix the P0123 Code?
The cost to fix the P0123 code can vary widely based on the underlying issues detected. Repairs can range from a simple cleaning of the Throttle Body (approximately $100-$200) to replacing sensors or wiring (potentially $200-$600 or more) depending on labor rates and parts costs in your area.
Can I Fix the P0123 Code Myself?
While some DIY enthusiasts may be able to tackle minor repairs like cleaning the Throttle Body or checking for loose connections, diagnosing and fixing electrical issues typically requires advanced knowledge and tools. If you are not confident in your abilities, seeking professional help is recommended to ensure proper diagnosis and repair.
