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Home >> Pontiac >> 2010 >> Vibe FWD L4-2.4L >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> P Code Charts >> P0121

P0121




DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135, or P2172

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 P0120
- Throttle Position (TP) Sensor 1 Circuit

DTC P0121
- Throttle Position (TP) Sensor 1 Performance

DTC P0122
- Throttle Position (TP) Sensor 1 Circuit Low Voltage

DTC P0123
- Throttle Position (TP) Sensor 1 Circuit High Voltage

DTC P0220
- Throttle Position (TP) Sensor 2 Circuit

DTC P0222
- Throttle Position (TP) Sensor 2 Circuit Low Voltage

DTC P0223
- Throttle Position (TP) Sensor 2 Circuit High Voltage

DTC P2135
- Throttle Position (TP) Sensor 1-2 Correlation

Diagnostic Fault Information





Typical Scan Tool Data









Circuit/System Description

The TP sensor used with the throttle actuator control (TAC) system is a Hall Effect switch. The Hall Effect switch is surrounded by a magnetic yoke that induces a flux in the magnetic field when the throttle shaft is rotated. The PCM provides a 5-volt reference voltage to the sensor circuits in the TAC module. An integrated circuit (IC) receives and converts the magnetic pulses into two separate TP signal, each with their own characteristics. The TP sensor 1 output provides the powertrain control module (PCM) with a signal voltage that is proportional to the throttle plate movement. Both TP sensor signal voltages are low at closed throttle and increase as the throttle opens. TP sensor 1 determines the actual throttle valve position. TP sensor 2 has a voltage that is greater than twice that of TP sensor 1 at idle. TP sensor 2 provides a backup value for TP sensor 1.

Conditions for Running the DTC

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

Conditions for Setting the DTC

P0120
* The PCM detects that the TP sensor 1 voltage is less than 0.5 volts.
OR
* The PCM detects that the TP sensor 1 voltage is greater than 4.5 volts.

P0121
* The difference between the TP sensor 1 and the TP sensor 2 voltage is less than 0.8 volts.
OR
* The difference between the TP sensor 1 and the TP sensor 2 voltage is greater than 1.6 volts.

P0122

The PCM detects that the TP sensor 1 voltage is less than 0.2 volts.

P0123

The PCM detects that the TP sensor 1 voltage is greater than 4.5 volts.

P0220
* The PCM detects that the TP sensor 2 voltage is less than 0.5 volts.
OR
* The PCM detects that the TP sensor 2 voltage is greater than 4.8 volts.

P0222

The PCM detects that the TP sensor 2 voltage is less than 0.5 volts.

P0223

The PCM detects that the TP sensor 2 voltage is greater than 4.8 volts.

P2135
* The PCM detects that the difference between TP sensor 1 and TP sensor 2 is less than 0.2 volts for greater than 0.6 seconds.
* The PCM detects that the TP sensor 1 voltage is less than 0.2 volts for greater than 0.4 seconds.
* The PCM detects that the TP sensor 2 voltage is less than 1.75 volts for greater than 0.4 seconds.

Action Taken When the DTC Sets

* DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and P2135 are Type A DTCs.
* The engine operates in the Reduced Engine Power Mode with the TP sensor 1 angle defaulted to 19 percent.

Conditions for Clearing the DTC

DTC P0120, P0121, P0122, P0123, P0220, P0222, P0223 and P2135 are Type A DTCs.

Diagnostic Aids

DTCs P0606 and P0607 indicate the 5-volt reference circuit shorted to ground. The engine may not start and the PCM may not communicate with the scan tool with this condition.

Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
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 that the scan tool TP sensor 1 parameter. The display should be between 7-19 percent.
2. Ignition ON, observe that the scan tool TP sensor 2 parameter. The display should be between 2.3-2.6 V.
3. Observe both scan tool TP sensor parameters while pressing the accelerator pedal from a closed throttle to wide open throttle (WOT). Both TP sensor parameters should change.
4. Rapidly depress the accelerator pedal from the rest position to the WOT position and release pedal. Repeat the procedure several times. DTCs P0120, P0121, P0122, P0123, P0220, P0222, P0223, or P2135 should not set.
5. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCs P0120, P0121, P0122, P0123, P0220, P0222, P0223, or P2135 should not set.
6. 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 throttle body assembly.
2. Ignition OFF, test for less than 10 ohm between the low reference circuit terminal 3 and ground G104.

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

3. Ignition ON, test for 4.8-5.2 V between the 5-volt reference circuit terminal 5 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 tests normal, replace the PCM.
• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PCM.

4. Test for 4.8-5.2 V between the TP senor signal circuit terminal listed below and ground.

* TP sensor 1 terminal 6
* TP sensor 2 terminal 4

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

5. If all circuits test normal, test or replace the throttle body assembly.

Repair Instructions

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

* Throttle Body Assembly Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for control module replacement, setup, and programming

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