P0123 - Throttle/Pedal Position Sensor/Switch A Circuit High Input
Meaning of P0123 Code
The P0123 code indicates that the Engine Control Module (ECM) has detected a
high voltage input from the Throttle/Pedal Position Sensor/Switch A circuit. This
means the throttle position sensor (TPS) is sending an abnormally high voltage signal
to the ECM, which could cause poor engine performance, stalling, or increased fuel
Step 1: Gather Necessary Tools
To diagnose and fix the P0123 code, you'll need the following tools:
- Diagnostic scan tool
- Basic hand tools
Step 2: Perform a Preliminary Inspection
Visually inspect the throttle body and TPS for any obvious damage, wear, or loose
connections. Also, check the wiring and connectors for any signs of damage or corrosion.
Step 3: Use a Diagnostic Scan Tool
Connect the diagnostic scan tool to the vehicle's OBD-II port and retrieve any
stored trouble codes and freeze frame data. This information can help you determine
when the problem occurred and under what conditions.
Step 4: Test the Throttle Position Sensor (TPS)
Using a multimeter, test the TPS for proper voltage and resistance values according
to the manufacturer's specifications. If the TPS is not within the specified range,
it may need to be replaced.
Step 5: Inspect the Wiring and Connectors
Check the wiring and connectors between the TPS and the ECM for any signs of
damage or corrosion. Repair or replace any damaged wiring or connectors as needed.
Step 6: Clear the Code and Test Drive
Once the issue has been resolved, use the diagnostic scan tool to clear the P0123
code. Test drive the vehicle to ensure the problem has been fixed and the code does
Step 7: Additional Considerations
If the problem persists after completing the steps above, you may need to consult
with a professional mechanic or refer to the vehicle's service manual for more specific