Throttle Position Sensor 1 Circuit High (Non ETC)

P0123-THROTTLE POSITION SENSOR 1 CIRCUIT HIGH (NON ETC)





For complete wiring diagrams refer to Diagrams/Electrical.


- When Monitored:

With the ignition on. Battery voltage greater than 10.4 volts.

- Set Condition:

Throttle Position Sensor voltage at the PCM is greater than 4.47 volts for 1.3 seconds. One Trip Fault. Three good trips to turn off the MIL.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Diagnostic Test


1. TP SENSOR VOLTAGE ABOVE 4.5 VOLTS

NOTE: Make sure the throttle is fully closed and free from binding or carbon build up.

NOTE: If a 5-volt Supply DTC has also set, diagnose the 5-volt DTC before continuing.

Start the engine and allow it to reach operating temperature.

With the scan tool select View DTCs.


NOTE: If the DTC does not reset it may be necessary to test drive the vehicle.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Go To 8

2. THROTTLE POSITION SENSOR





Turn the ignition off.

Disconnect the TP Sensor harness connector.

Connect a jumper wire between the (K22) TP Sensor No.1 Signal circuit and the (K900) Sensor ground circuit in the Sensor harness connector.

With a scan tool, monitor the TP Sensor voltage.

Ignition on, engine not running.


NOTE: The sensor voltage should be approximately 0.0 volts (plus or minus .1 volt) with the jumper wire in place.

Does the scan tool display the voltage as described above?

Yes

- Replace the Throttle Position Sensor.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 3

NOTE: Remove the jumper wire before continuing.

3. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO VOLTAGE





Turn the ignition off.

Disconnect the C2 PCM harness connector.

Ignition on, engine not running.

Measure the voltage on the (K22) TP Sensor No.1 Signal circuit in the TP Sensor harness connector.

Is there any voltage present?

Yes

- Repair the short to voltage in the (K22) TP Sensor No.1 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 4

4. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT OPEN





Turn the ignition off.


CAUTION: Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K22) TP Sensor No.1 Signal circuit from the TP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 5

No

- Repair the open in the (K22) TP Sensor No.1 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

5. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT





Measure the resistance between the (K22) TP Sensor No.1 Signal circuit and the (F855) 5-volt Supply circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between the (F855) 5-volt Supply circuit and the (K22) TP Sensor No.1 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. (K900) SENSOR GROUND CIRCUIT OPEN





Measure the resistance of the (K900) Sensor ground circuit from the TP Sensor harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 7

No

- Repair the open in the (K900) Sensor ground circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

7. PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. THROTTLE POSITION SENSOR SWEEP

With a scan tool, monitor the Throttle Position Sensor voltage.

Slowly open the throttle from the idle position to the wide open throttle position.

Does voltage start at approximately 0.8 of a volt and go above 3.5 volts with a smooth transition?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition


No

- Replace the Throttle Position Sensor.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test