P0122-THROTTLE POSITION SENSOR 1 CIRCUIT LOW (NON ETC)
For a complete wiring diagram Refer to Section 8W.
- 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.
| Possible Causes |
| (F855) 5-VOLT SUPPLY CIRCUIT OPEN |
| (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND |
| (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO GROUND |
| (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT |
| THROTTLE POSITION SENSOR |
| PCM |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1. THROTTLE POSITION SENSOR VOLTAGE BELOW 0.098 OF A VOLTIgnition on, engine not running.
With a scan tool, read the TP Sensor voltage.
Is the voltage below 0.098 of a volt?
Yes
- Go To 2
No
- Go To 9
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 6
3. THROTTLE POSITION SENSOR
With a scan tool, monitor the TP Sensor voltage with the Sensor harness connector disconnected.
Is the voltage above 4.5 volts?
Yes
- Replace the Throttle Position Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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 the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
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 the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 8
6. (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 7
No
- Repair the open in the (F855) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
7. (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 the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 8
8. 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 the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Replace and program the Powertrain Control Module per Service Information.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
9. 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.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Replace the Throttle Position Sensor.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)