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 P1516: Throttle Actuator Control (TAC) Module Throttle Actuator Position Performance
DTC P2101: Throttle Actuator Position Performance
DTC P2119: Throttle Closed Position Performance
DTC P2176: Minimum Throttle Position Not Learned

### Circuit/System Description

The engine control module (ECM) controls the throttle valve by applying a varying voltage to the control circuits of the throttle actuator control (TAC) motor. The ECM monitors the duty cycle that is required to actuate the throttle valve. The ECM monitors the throttle position (TP) sensors 1 and 2 to determine the actual throttle valve position.

### Conditions for Running the DTC

#### P1516 or P2101

• | DTC P1682 not set - P2101.

• | The engine is running.

• | The ECM has learned the minimum throttle position.

• | The ignition voltage is greater than 6 volts and reduced power is not active.

• | DTCs P1516 and P2101 run continuously when the above conditions are met.

#### P2119

• | DTCs P0121, P0122, P0123, P0222, P0223, P0641, P0651, P0697, P06A3, or P2135 are not set.

• | The ignition voltage is greater than 6 volts.

• | DTC P2119 runs when the ignition is turned to the OFF position, when the above conditions are met.

#### P2176

• | The ignition voltage is greater than 6 volts.

• | DTC P2176 runs once per ignition cycle when the above conditions are met.

### Conditions for Setting the DTC

#### P1516 and P2101

The ECM detects the difference between the actual throttle position, and the desired position is greater than 7.5 percent for 30 seconds.

#### P2119

The ECM detects that the throttle blade did not return to the default position, during power down, within a calibrated amount of time.

#### P2176

The ECM detects that both throttle position (TP) sensors were greater than 0.95 volts during the minimum learn procedure.

### Action Taken When the DTC Sets

#### P1516, P2101, or P2176

• | DTCs P1516, P2101, and P2176 are Type A DTCs.

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

• | DTCs P2106 and P2110 will set.

#### P2119

DTC P2119 is a Type C DTC.

### Conditions for Clearing the DTC

• | DTC P2119 is a Type C DTC.

• | DTCs P1516, P2101, and P2176 are Type A DTCs.

### Diagnostic Aids

• | A high resistance condition with the TP sensor circuits could cause DTCs P1516, P2101, P2119, or P2176 to set.

• | Inspect for a condition in which the throttle valve may have been held open. For example, ice may have formed in the throttle bore causing the throttle valve not to close.

### 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 DTCs P0121, P0122, P0123, P0222, P0223 or P2135 should not set.

⇒ | If any of the DTCs are set refer to DTC P0121-P0123, P0222, P0223, or P2135 for further diagnosis.

2. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release pedal. Repeat the procedure several times. DTCs P1516, P2101, P2119, or P2176 should not set.
3. Slowly depress the accelerator pedal to WOT and then slowly return the pedal to closed throttle. Repeat the procedure several times. DTCs P1516, P2101, P2119, or P2176 should not set.
4. Engine idling, observe the TAC Command parameter with a scan tool. The reading should display greater than 0 %.
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. Inspect the throttle body for the following conditions:

• | A throttle blade that is not in the rest position

• | A throttle valve that is binding open or closed

• | A throttle valve that opens or closes without spring pressure

⇒ | If any condition is found, replace the throttle body.

Note: Disconnecting the throttle body harness connector causes additional DTCs to set.

2. Ignition OFF, disconnect the harness connector at the throttle body.
3. Ignition ON, test for greater than 9 V on the motor control 1 circuit terminal A and motor control 2 circuit terminal B.

⇒ | If less than the specified range, test the appropriate motor control circuit for a short to ground, or an open/high resistance. If the circuit tests normal, replace the ECM.

4. Ignition ON, probe the motor control 1 circuit terminal A and motor control 2 circuit terminal B with a test lamp connected to ground. Verify the test lamp does not illuminate.

⇒ | If the test lamp illuminates, test the appropriate motor control circuit for a short to voltage. If the circuit tests normal, replace the ECM.

5. Set the DMM to AC hz on the 400 mV scale. Engine idling, test for greater than 2,000 AC hz between the motor control circuits listed below and ground while commanding the Engine Speed to 1,950 RPM with a scan tool.

• | Motor control 1 circuit terminal A

• | Motor control 2 circuit terminal B

⇒ | If less than the specified value, replace the ECM.

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

### 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