DTC P0123 - Throttle Position (TP) Sensor: Condition

This code indicates TP signal is more than self-test maximum. Possible causes for this fault are:

• TP sensor not seated correctly.
• Faulty TP sensor.
• TP circuit shorted to VREF or VPWR.
• VREF circuit shorted to VPWR.
• Open in SIG RTN circuit.
• Faulty PCM.

1)  Turn ignition off. Disconnect TP sensor wiring harness connector. Inspect for damage and repair as necessary. Turn ignition on. Access TP PID on scan tool. If PID voltage is 0.17 volt or more, go to step 10). If PID voltage is less than 0.17 volt, go to next step.

2) Check VREF Circuit Voltage  With TP sensor disconnected, turn ignition on. Measure voltage between VREF and SIG RTN terminals at TP sensor wiring harness connector. If reading is 4-6 volts, go to next step. If reading is not 4-6 volts, inspect VREF circuit for open or short. Repair as needed.

3) Check TP Circuit For Short To Power  Turn ignition off. Leave TP sensor disconnected. Disconnect PCM 104-pin connector. Inspect connector for damage and repair as necessary. Install Breakout Box (014-00950), leaving PCM disconnected. Measure resistance between test pin No. 89 (TP) and test pins No. 71, 90 and 97 (VPWR) at breakout box. If any resistance is less than 10,000 ohms, repair TP circuit short to VREF and repeat QUICK TEST. If each resistance is 10,000 ohms or more, replace PCM and repeat QUICK TEST.