DTC Troubleshooting: P0122 (7-1)

DTC P0122 (7-1):  TP Sensor Circuit Low Voltage

1.Turn the ignition switch ON(II).

2.Check the throttle position with the scan tool.

Is there about 10% or 0.5 V when the throttle is fully closed and about 90% or 4.5 V when the throttle is fully opened?


YES - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the TP sensor and at the ECM/PCM.n


NO - Go to 3.


3.Turn the ignition switch OFF.

4.Disconnect the TP sensor 3P connector.

5.Turn the ignition switch ON (II).

6.Measure voltage between the TP sensor 3P connector terminals No. 1 and No. 3.

 

Is there about 5 V?


YES - Go to 7.


NO - Go to 14.


7.Turn the ignition switch OFF.

8.At the sensor side, measure resistance between the TP sensor 3P connector terminals No. 1 and No. 2 with the throttle fully closed.

 

Is there about 0.5-0.9 kW?


YES - Go to 9.


NO - Replace the throttle body.n


9.Measure resistance between the TP sensor 3P connector terminals No. 2 and No. 3 with the throttle fully closed.

 

Is there about 4.5kW?


YES - Go to 10.


NO - Replace the throttle body.n


10.Disconnect ECM/PCM connector A (31P).

11.At the wire harness side, check for continuity between TP sensor 3P connector terminal No. 2 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the ECM/PCM (A15) and the TP sensor.n


NO - Go to 12.


12.Connect ECM/PCM connector terminal A15 and body ground with a jumper wire.

 

13.At the wire harness side, check for continuity between TP sensor 3P connector terminals No. 2 and body ground.

 

Is there continuity?


YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.n


NO - Repair open in the wire between the ECM/PCM (A15) and the TP sensor.n


14.Measure voltage between ECM/PCM connector terminals A10 and A20.

 

Is there about 5 V?


YES - Repair open in the wire between the ECM/PCM (A20) and the TP sensor.n


NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.n