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Throttle Position Sensor 1 Circuit Low (Non ETC)






P0122-THROTTLE POSITION SENSOR 1 CIRCUIT LOW (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 less than 0.0978 of a volt 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. THROTTLE POSITION SENSOR VOLTAGE BELOW 0.098 OF A VOLT

Start the engine and allow it to reach operating temperature.


WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

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 10

2. (F855) 5-VOLT SUPPLY CIRCUIT





Turn the ignition off.

Disconnect the TP Sensor harness connector.

Ignition on, engine not running.

Measure the voltage on the (F855) 5-volt Supply circuit in the TP Sensor harness connector.

Is the voltage between 4.5 to 5.2 volts?

Yes

- Go To 3

No

- Go To 7

3. THROTTLE POSITION SENSOR

With the a scan tool, monitor the TP Sensor voltage with the Sensor harness connector disconnected.


NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus .1 volt) with the connector disconnected.

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 4

4. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND





Turn the ignition off.

Disconnect the C2 PCM harness connector.

Measure the resistance between ground and the (K22) TP Sensor No.1 Signal circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

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

No

- Go To 5

5. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT





Measure the resistance between the (K22) TP Sensor No.1 Signal circuit and the (K900) Sensor ground circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between the (K900) Sensor ground and the (K22) TP Sensor No.1 Signal circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. (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 9

No

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

7. (F855) 5-VOLT SUPPLY CIRCUIT OPEN





Turn the ignition off.

Disconnect the C2 PCM harness connector.


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 (F855) 5-volt Supply 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 8

No

- Repair the open in the (F855) 5-volt Supply circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

8. (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND





Measure the resistance between ground and the (F855) 5-volt Supply circuit in the TP Sensor harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (F855) 5-volt Supply circuit.
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 9

9. 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

10. 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
- Perform POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

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