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 | P0122, P0222, P0641, P2106, P2110 | -- | P0122, P0222, P2106, P2110, P2135 | P0223, P0641, P2106, P2110, P2135 | --
TP Sensor 1 Signal | P0122, P2135 | P2135 | P0123, P2135 | P0123, P2135 | P2135
TP Sensor 2 Signal | P0222, P2135 | P2135 | P0222, P2135 | P0223, P2135 | P2135
Low Reference | -- | -- | P0123, P2106, P2110 | -- | --

### Typical Scan Tool Data

#### TP Sensor 1

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: The ignition is ON and the engine is OFF. Parameter Normal Range: TP Sensor 1 7-21%
5-Volt Reference | 0% | 0% | 30-40%
TP Sensor 1 Signal | 0% | 80-90% | 85-99%
Low Reference | -- | 85-95% | --

#### TP Sensor 2

Circuit | Short to Ground | Open | Short to Voltage
--- | --- | --- | ---
Operating Conditions: The ignition is ON and the engine is OFF. Parameter Normal Range: TP Sensor 2 7-21%
5-Volt Reference | 80-90% | 80-90% | 0%
TP Sensor 2 Signal | 80-90% | 80-90% | 0%
Low Reference | -- | 0% | --

### 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.

### 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

#### P0122

The ECM detects that the TP sensor 1 voltage is less than 0.25 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 0.25 volt for less than 1 second.

#### P0223

The ECM detects that the TP sensor 2 voltage is greater than 4.8 volts for less than 1 second.

#### P2135

The ECM detects that TP sensor 1 and TP sensor 2 disagree greater than 4.5 percent for less than 1 second.

### Action Taken When the DTC Sets

#### DTC P0122 or P0123

• | DTC P0122 and P0123 are type B DTCs

• | The ECM uses throttle position (TP) sensor 2 for throttle control.

#### DTC P0222 or P0223

• | DTC P0222 and P0223 are type B DTCs

• | The ECM uses throttle position (TP) sensor 1 for throttle control.

#### DTC P2135

• | DTC P2135 is a type A DTC.

• | The ECM commands the TAC system to operate in a Reduced Engine Power mode.

• | The ECM commands the reduced engine power indicator ON.

### Conditions for Clearing the DTC

• | DTCs P0122, P0123, P0222, and P0223 are type B DTCs.

• | DTC P2135 is a type A DTC.

### Diagnostic Aids

• | If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, other 5-volt reference circuits may be affected.

• | The scan tool 5-volt reference parameter should display between 4.8-5.2 volts.

### 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. DTC P0641 should not set.

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

2. Ignition ON, observe the scan tool TP Sensor percentage parameters. The readings should be between 7-21 %.
3. Observe both scan tool TP Sensor percentage parameters while pressing the accelerator pedal from a closed throttle to wide open throttle (WOT). Both 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 P0122, P0123, 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 P0122, P0123, 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 5 ohms or less of resistance between the low reference circuit terminal 1 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 volts between the 5-volt reference circuit terminal 4 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. Verify both scan tool TP sensor percentage parameters are between 80-88 %.

⇒ | If TP sensor 1 is less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

⇒ | If TP sensor 1 is greater than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

⇒ | If TP sensor 2 is less than specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.

⇒ | If TP sensor 2 is greater than specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the ECM.

5. Install a 3A fused jumper wire between TP sensor 1 signal circuit terminal 2 and ground. Verify the scan tool TP sensor 1 percentage parameter is less than 2 %.

⇒ | If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

6. Install a 3A fused jumper wire between TP sensor 2 signal circuit terminal 3 and the 5-volt reference circuit. Verify the scan tool TP sensor 2 percentage parameter is less than 2 %.

⇒ | If greater than the specified range, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.

7. If all circuits test normal, 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 engine control module replacement, setup, and programming