Gas

P0122-THROTTLE POSITION SENSOR 1 CIRCUIT LOW





For a complete wiring diagram refer to Diagrams/Electrical.

- When Monitored:

With the ignition on. Battery voltage greater than 10 volts.

- Set Condition:

Throttle Position Sensor voltage at the PCM is less than 0.16 of a volt for 0.7 of a second. One Trip Fault. Three good trips to turn off the MIL. ETC light will illuminate.







Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.


Diagnostic Test

1. ACTIVE DTC


NOTE: Diagnose and repair any Throttle Body circuit, system voltage, or sensor supply voltage DTCs before continuing with this test.

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.


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. (K855) 5-VOLT SUPPLY CIRCUIT





Turn the ignition off.

Disconnect the Throttle Body harness connector.

Ignition on, engine not running.

Measure the voltage on the (K855) 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

With a scan tool, monitor the TP Sensor No.1 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

- Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, using a scan tool select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 5

5. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO GROUND





Turn the ignition off.

Disconnect the C2 PCM harness connector.

Measure the resistance between ground and the (K22) TP Signal 1 circuit in the Throttle Body harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (K22) TP Signal 1 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 6

6. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K922) SENSOR RETURN CIRCUIT





Measure the resistance between the (K22) TP Signal 1 circuit and the (K922) Sensor Return circuit in the Throttle Body harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between the (K922) Sensor Return circuit and the (K22) TP Signal 1 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 7

7. EXCESSIVE RESISTANCE IN THE (K22) TP SIGNAL 1 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 Miller Special Tool #8815 to perform diagnosis.

Measure the resistance of the (K22) TP Signal 1 circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

Is the resistance below 5.0 ohms?

Yes

- Go To 10

No

- Repair the excessive resistance in the (K22) TP Signal 1 circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


8. (K855) 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 diagnostics.

Measure the resistance of the (K855) 5-volt Supply circuit from the Throttle Body 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 (K855) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test


9. (K855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND





Measure the resistance between ground and the (K855) 5-volt Supply circuit in the Throttle Body harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short to ground in the (K855) 5-volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Go To 10


10. 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. Powertrain Verification Test

No

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


11. THROTTLE FOLLOWER TEST

With a scan tool, perform the Throttle Follower Test.

Monitor the TP Sensor No.1 voltage.

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

- Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, using a scan tool select ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test