For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0122: Throttle Position (TP) Sensor 1 Circuit Low Voltage
DTC P0123: Throttle Position (TP) Sensor 1 Circuit High Voltage
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

Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | --- | ---
5-Volt Reference | P06A3 | -- | P0122, P0222, | P0223, P06A3, P2135 | --
TP Sensor 1 Signal | P0122 | P2119, P2135, P2176 | P0122 | P0123, P2135 | P2135
TP Sensor 2 Signal | P0222 | P2135 | P0223 | P0223, P2135 | P2135
Low Reference | -- | -- | P0123, P0223 | -- | --

### Typical Scan Tool Data

#### TP Sensor 1

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: The engine is idling. Parameter Normal Range: TP Sensor 1 3.8-4.4 V
5-Volt Reference | 0.00 V | 0.00 V | 5.00 V
TP Sensor 1 Signal | 0.00 V | 0.00 V | 5.00 V
Low Reference | -- | 4.98 V | --

#### TP Sensor 2

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: The engine is idling. Parameter Normal Range: TP Sensor 2 0.75-1.02 V
5-Volt Reference | 0.02 V | 0.00 V | 5.00 V
TP Sensor 2 Signal | 0.00 V | 5.00 V | 5.00 V
Low Reference | -- | 5.00 V | --

### Circuit/System Description

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

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

### Conditions for Running the DTC

#### P0121

• | DTCs P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0335, or P0336 is 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, P0123, P0222, P0223

• | DTCs P0641, or P06A3 are not set.

• | The ignition is ON, or the engine is running.

• | The engine is not operating in reduced power mode.

• | The ignition voltage is greater than 6 volts.

• | The DTCs runs continuously when the above condition is met.

#### P2135

• | DTCs P0122, P0123, P0222, P0223, P0641, or P06A3 are not set.

• | The ignition is ON, or the engine is running.

• | The engine is not operating in reduced power mode.

• | The ignition voltage is greater than 6 volts.

• | The DTCs runs continuously when the above condition is met.

### Conditions for Setting the DTC

#### P0121

The ECM detects that the TP sensor 1 voltage is stuck in range for less than 1 second.

#### P0122

The ECM detects that the TP sensor 1 voltage is less than 0.3 volt for less than 1 second.

#### P0123

The ECM detects that the TP sensor 1 voltage is greater than 4.8 volts for less than 1 second.

#### P0222

The ECM detects that the TP sensor 2 voltage is less than 0.3 volt for less than 1 second.

#### P0223

The ECM detects that the TP sensor 2 voltage is greater than 4.6 volts for less than 1 second.

#### P2135

The ECM detects that TP sensor 1 and TP sensor 2 disagree greater than 5 percent for less than 1 second.

### Action Taken When the DTC Sets

#### P0121

• | DTC P0121 is a type B DTC

• | The ECM commands the throttle actuator control (TAC) system to operate in a Reduced Engine Power mode.

#### P0122, P0123, P0222, P0223, or P2135

• | DTC P0122, P0123, P0222, P0223, and P2135 are type A DTCs

• | The ECM commands the throttle actuator control (TAC) system to operate in a Reduced Engine Power mode.

### Conditions for Clearing the DTC

• | DTC P0121 is a type B DTC.

• | DTCs P0122, P0123, P0222, P0223 and P2135 is a type A DTC.

### Diagnostic Aids

• | It may be necessary to disconnect the battery to clear DTC P2135.

• | A high resistance condition on the throttle actuator control circuits could cause a DTC to set.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Throttle Actuator Control (TAC) System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

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

⇒ | If the DTC is set, refer to DTC P0641, P0651, P0697, or P06A3.

2. Ignition ON, observe both TP Sensor voltage parameters with a scan tool. Verify the scan tool TP sensor parameters are between 0.50-4.5 V.
3. Observe the scan tool TP 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 TP sensor 1 and 2 Agree/Disagree parameter should display Agree.

4. Observe the DTC Information with a scan tool. DTCs P0121, P0122, P0123, P0221, P0222, and P0223 should not set.
5. Observe both TP Sensor percentage parameters while quickly pressing the accelerator pedal from a closed throttle to WOT. Both TP Sensor percentage parameters should change.
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 for 1 minute, test for less than 5 Ω between the low reference circuit terminal E and ground.

⇒ | 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 ECM.

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

⇒ | If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.

4. Test for less than 1 volt between the TP 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 ECM.

5. Test for 4.8-5.2 V between the TP 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 ECM.

⇒ | If greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

6. Install a 3 A fused jumper wire between TP sensor 1 signal circuit terminal F and the 5-volt reference circuit terminal C. Verify the scan tool TP 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 ECM.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Throttle Body Assembly Replacement

• | Control Module References for ECM replacement, setup, and programming