Powertrain Management (w/o Throttle Actuator Control)

DTC P0122 or P0123 (w/o Throttle Actuator Control)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Strategy Based Diagnosis Strategy Based Diagnosis
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions

DTC Descriptors
DTC P0122
- Throttle Position (TP) Sensor Circuit Low Voltage

DTC P0123
- Throttle Position (TP) Sensor Circuit High Voltage

Diagnostic Fault Information






Typical Scan Tool Data






Circuit/System Description

The throttle body assembly contains a throttle position (TP) sensor. The TP sensor is mounted externally on the throttle body assembly. The TP sensor is a potentiometer which provides a signal voltage that changes relative to the throttle blade angle. The engine control module (ECM) supplies the TP sensor with a 5-volt reference circuit, a low reference circuit, and a signal circuit. The TP sensor signal voltage decreases from less than 1 volt at idle to more than 4 volts at wide open throttle (WOT).

Conditions for Running the DTC

* The ignition is ON or the engine is operating.
* The DTCs runs continuously when the above condition is met.

Conditions for Setting the DTC

Important: The scan tool displays a voltage near 0.0 volts. Do not use the scan tool voltage parameter to determine if there is a TP sensor condition.


P0122

The ECM detects that the TP sensor voltage is less than 0.14 volt for more than 5 seconds.

P0123

The ECM detects that the TP sensor voltage is more than 4.9 volts for more than 5 seconds.

Action Taken When the DTC Sets

DTC P0122 and P0123 are Type A DTCs.

Conditions for Clearing the DTC

DTC P0122 and P0123 are Type A DTCs.

Reference Information

Schematic Reference

Engine Controls Schematics (w/Throttle Actuator Controls) Electrical DiagramsEngine Controls Schematics (w/o Throttle Actuator Control) Electrical Diagrams

Connector End View Reference
* Engine Control Module Connector End Views (w/ Throttle Actuator Control) Engine Control Module Connector End Views (w/ Throttle Actuator Control)Engine Control Module Connector End Views (w/o Throttle Actuator Control) Engine Control Module Connector End Views (w/o Throttle Actuator Control)
* Engine Controls Connector End Views (w/ Throttle Actuator Control) Engine Controls Connector End Views (w/ Throttle Actuator Control)Engine Controls Connector End Views (w/o Throttle Actuator Control) Engine Controls Connector End Views (w/o Throttle Actuator Control)

Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference
* Scan Tool Data List (w/ Throttle Actuator Control) Scan Tool Data List (w/ Throttle Actuator Control)Scan Tool Data List (w/o Throttle Actuator Control) Scan Tool Data List (w/o Throttle Actuator Control)
* Scan Tool Data Definitions (w/ Throttle Actuator Control) Scan Tool Data Definitions (w/ Throttle Actuator Control)Scan Tool Data Definitions (w/o Throttle Actuator Control) Scan Tool Data Definitions (w/o Throttle Actuator Control)
* Scan Tool Output Controls (w/ Throttle Actuator Control) Scan Tool Output Controls (w/ Throttle Actuator Control)Scan Tool Output Controls (w/o Throttle Actuator Control) Scan Tool Output Controls (w/o Throttle Actuator Control)

Circuit/System Verification

Start the engine, observe the TP Sensor voltage parameter with a scan tool. The parameters should be between 0.4-4.5 volts.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector of the TP sensor.
2. Test for less than 5 ohms of resistance between the low reference circuit and ground.

• If greater than the specified value, test the low reference circuit for a short to voltage or an open/high resistance. If the circuit/connections test normal, replace the ECM.

Important: The 5-volt reference circuits are internally and externally connected at the ECM. Other component DTCs may be set. If other DTCs are set, review the electrical schematic and diagnose the applicable circuits and components.


3. Ignition ON, load test for 4.8-5.2 volts between the 5-volt reference circuit and ground.

• If less than the specified range, test the 5-volt reference circuit for a short to ground or open/high resistance. If the circuit/connections test normal, replace the ECM.

• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit/connections test normal, replace the ECM.

4. Verify that the scan tool TP sensor voltage parameter is less than 0.3 volt.

• If greater than the specified value, test the signal circuit for a short to voltage. If the circuit/connections test normal, replace the engine control module (ECM).

5. Install a 3-amp fused jumper wire between the signal circuit and the 5-volt reference circuit. Verify that the scan tool TP sensor voltage parameter is greater than 4.8 volts.

• If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit/connections test normal, replace the engine control module (ECM).

6. If all circuits/connections test normal, test or replace the TP sensor.

Component Testing

1. Turn OFF the ignition.
2. Measure for 5150-5350 ohms between the 5-volt reference and the low reference terminals of the TP sensor.

• If the resistance is not within the specified range, replace the TP sensor.

3. Measure the resistance between the signal terminal and the low reference terminal of the TP sensor. Slowly sweep the TP sensor through the entire range several times. The resistance should vary between 2500 and 6800 ohms without any spikes or dropouts.

• If the resistance is not within the specified range or is erratic, replace the TP sensor.

4. Apply 5 volts and ground to the applicable terminals of the TP sensor, and measure the voltage between the signal and the low reference terminals. Slowly sweep the TP sensor through the entire range several times. The voltage should vary between 0.6-4.7 volts without any spikes or dropouts.

• If the voltage is not within the specified range or is erratic, replace the TP sensor.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.

* Throttle Position Sensor Replacement (wo/Throttle Actuator Control) Service and Repair
* Control Module References Control Module References for engine control module replacement, setup, and programming