Operation CHARM: Car repair manuals for everyone.
Home >> Chevrolet >> 2011 >> Cruze L4-1.8L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0123

P0123




DTC P0121-P0123, P0222, P0223, or P2135

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

DTC Descriptors
DTC P0121 00
- Throttle Position Sensor Performance

DTC P0122 00
- Throttle Position Sensor 1 Circuit Low Voltage

DTC P0123 00
- Throttle Position Sensor 1 Circuit High Voltage

DTC P0222 00
- Throttle Position Sensor 2 Circuit Low Voltage

DTC P0223 00
- Throttle Position Sensor 2 Circuit High Voltage

DTC P2135 00
- Throttle Position Sensors 1-2 Not Plausible

Diagnostic Fault Information





Typical Scan Tool Data










Circuit/System Description

The throttle body assembly contains 2 throttle position sensors. The throttle position sensors are mounted to the throttle body assembly and are not serviceable. The throttle position sensors provide a signal voltage that changes relative to throttle blade angle. The engine control module (ECM) supplies the throttle position sensors with a common 5 V reference circuit , a common low reference circuit, and two independent signal circuits.

The throttle position sensors have opposite functionality. Throttle position sensor 1 signal voltage decreases and throttle position sensor 2 signal voltage increases as the accelerator pedal increases to wide open throttle (WOT).

Conditions for Running the DTC

* DTC P0641 00 or P0651 00 are not set.
* The run/crank or powertrain relay voltage is greater than 6 V and reduced power is not active.
* The ignition is ON or the engine is operating.
* DTC P0122 00, P0123 00, P0222 00, P0223 00, and P2135 00 run continuously when the above conditions are met.

Conditions for Setting the DTC

P0121 00
* DTCs P0102 00, P0103 00, P0107 00, P0108 00, P0112 00, P0113 00, P0117 00, P0118 00, P0335 00, or P0336 00 are not set.
* The engine speed is between 400-6 500 RPM.
* The engine coolant temperature (ECT) is between 70-125°C (158-257°F).
* The intake air temperature (IAT) is between -20 to +125°C (-4 to +257°F).
* The DTC runs continuously when the above conditions are met.

P0122 00

The ECM detects that the throttle position sensor 1 voltage is less than 0.325 V for greater than 1 s.

P0123 00

The ECM detects that the throttle position sensor 1 voltage is greater than 4.75 V for greater than 1 s.

P0222 00

The ECM detects that the throttle position sensor 2 voltage is less than 0.25 V for greater than 1 s.

P2135 00

The difference between the throttle position sensor 1 and throttle position sensor 2 exceeds a predetermined value for greater than 1 s.

Action Taken When the DTC Sets

* DTCs P0121 00, P0122 00, P0123 00, P0222 00, P0223 00, and P2135 00 are Type A DTCs.
* The control module commands the throttle actuator control (TAC) system to operate in the Reduced Engine Power mode.
* A message center or an indicator displays Reduced Engine Power.
* Under certain conditions the control module commands the engine OFF.

Conditions for Clearing the DTC

DTCs P0121 00, P0122 00, P0123 00, P0222 00, P0223 00, and P2135 00 are Type A DTCs.

Diagnostic Aids

* It may be necessary to disconnect the battery to clear DTC P2135 00
* A high resistance condition on the throttle position and throttle actuator control circuits could cause a DTC to set.

Reference Information
Schematic Reference

Engine Controls Schematics ([1][2]Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Throttle Actuator Control (TAC) System Description (Throttle Actuator Control (TAC) System Description)
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

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTC P06A3 00 is not set.

• If a DTC is set, refer to DTC P0641, P0651, P0697, or P06A3 (P0641) for further diagnosis.

2. Ignition ON, observe both Throttle Position Sensor voltage parameters with a scan tool. Verify the scan tool Throttle Position Sensor parameters are between 0.50-4.5 V.
3. Observe the scan tool Throttle Position Sensor 1 and 2 Agree/Disagree parameter while performing the following tests:

* Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times.
* Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times.

• The Throttle Position Sensor 1 and 2 Agree/Disagree parameter should display Agree.

4. Observe the DTC Information with a scan tool. DTCs P0121 00, P0122 00, P0123 00, P0221 00, P0222 00, and P0223 00 should not be set.
5. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data..

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the Q38 Throttle Body.
2. Ignition OFF and all vehicle systems OFF. It may take up to 2 min for all vehicle systems to power down. Test for less than 5 ohm between the low reference circuit terminal E and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

3. Ignition ON, test for 4.8-5.2 V between the 5 V reference circuit terminal C and ground.

• If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

4. Test for less than 1 V between the throttle position sensor 1 signal circuit terminal F and ground.

• If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

5. Test for 4.8-5.2 V between the throttle position sensor 2 signal circuit terminal D and ground.

• If less than specified range, test the signal circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

6. Install a 3 A fused jumper wire between throttle position sensor 1 signal circuit terminal F and the 5 V reference circuit terminal C. Verify the scan tool Throttle Position sensor 1 voltage parameter is greater than 4.8 V.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.

7. Test for 4.8-5.2 V between the throttle position sensor 2 signal circuit terminal F and ground.

• If less than specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 Engine Control Module.
• If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.

8. If all circuits and connections test normal, replace the Q38 Throttle Body.

Repair Instructions

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

* Throttle Body Assembly Replacement (1.6L LDE, LXV, 1.8L 2H0, and LUW) (Removal and Replacement)
* Control Module References (Programming and Relearning)for ECM replacement, setup, and programming

pro multis · About Operation CHARM