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Powertrain Control Module (PCM) - NGC






P0122-THROTTLE POSITION SENSOR 1 CIRCUIT LOW

Special Tools:










For a complete wiring diagram Refer to the Wiring Information.

- When Monitored:
With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:
Throttle Position Sensor voltage at the PCM is less than the minimum acceptable voltage. One Trip Fault. Three good trips to turn off the MIL. ETC light will illuminate.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. ACTIVE DTC

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

1. 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 may result in possible serious or fatal injury.

2. With the scan tool select View DTCs.

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

NOTE: If the P2122-APP Sensor 1 Circuit Low DTC is also Active, diagnose the P2122 before continuing with the P0122 diagnostic procedure.

Is the DTC Active at this time?

Yes

- Go To 2

No

- Go To 11

2. P0222 ALSO SET

Was the P0222-TP SENSOR NO.2 VOLTAGE LOW DTC set along with the P0122?

Yes

- Go To 3

No

- Go To 4

3. (F855) 5-VOLT SUPPLY CIRCUIT




1. Turn the ignition off.
2. Disconnect the Throttle Body harness connector.
3. Ignition on, engine not running.
4. Measure the voltage on the (F855) 5-volt Supply circuit in the Throttle Body harness connector.

Is the voltage between 4.8 to 5.2 volts?

Yes

- Go To 4

No

- Go To 8

4. THROTTLE POSITION SENSOR
1. With a scan tool, monitor the TP Sensor No.1 voltage with the Throttle Body 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

- Verify that there is good pin to terminal contact at the Throttle Body and the Powertrain Control Module connectors. Replace the Throttle Body Assembly if no problems were found in the connectors. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

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




1. Turn the ignition off.
2. Disconnect the C2 PCM harness connector.
3. Measure the resistance between ground and the (K22) TP Sensor No.1 Signal circuit in the Throttle Body 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. Powertrain Verification Test

No

- Go To 6

6. (K22) TP SENSOR NO.1 SIGNAL CIRCUIT SHORTED TO THE (K922) TP SENSOR RETURN CIRCUIT




1. Measure the resistance between the (K22) TP Sensor No.1 Signal circuit and the (K922) TP Sensor Return circuit in the Throttle Body harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between the (K922) TP Sensor Return circuit and the (K22) TP Sensor No.1 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 7

7. EXCESSIVE RESISTANCE IN THE (K22) TP SENSOR NO.1 SIGNAL CIRCUIT





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 the PCM Pinout Box (8815A) to perform diagnosis.

1. Measure the resistance of the (K22) TP Sensor No.1 Signal circuit between the Throttle Body harness connector and the appropriate terminal of special tool #.

Is the resistance below 5.0 ohms?

Yes

- Go To 10

No

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

8. (F855) 5-VOLT SUPPLY CIRCUIT OPEN




1. Turn the ignition off.
2. 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 the PCM Pinout Box (8815A) to perform diagnostics.

3. Measure the resistance of the (F855) 5-volt Supply circuit from the Throttle Body harness connector to the appropriate terminal of special tool #.

Is the resistance below 5.0 ohms?

Yes

- Go To 9

No

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

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




1. Measure the resistance between ground and the (F855) 5-volt Supply circuit in the Throttle Body 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. Powertrain Verification Test

No

- Go To 10

10. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors.
4. Search for any Technical Service Bulletins that may apply.

Were there any problems found?

Yes

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

No

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

11. THROTTLE FOLLOWER TEST
1. With a scan tool, perform the ETC Throttle Follower Test.
2. Monitor the TP Sensor No.1 voltage.

Does voltage start at approximately 0.7 of a volt to approximately 4.3 volts with a smooth transition?

Yes

- Refer to the INTERMITTENT CONDITION Diagnostic Procedure. Intermittent Condition Test

No

- Verify that there is good pin to terminal contact at the Throttle Body and the Powertrain Control Module connectors. Replace the Throttle Body Assembly if no problems were found in the connectors. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

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