Diagnostic Instructions

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) is the control center for the throttle actuator control (TAC) system. The ECM controls the throttle valve by applying a pulse width modulated 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, P2119 and P2101

P2176

Conditions for Setting the DTC

P1516 and P2101

The indicated throttle position does not match the predicted throttle position for greater than 0.5 second

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 difference between the predicted and the actual throttle position is more than a calibrated amount for greater than 1.5 seconds.

Action Taken When the DTC Sets

Conditions for Clearing the DTC

Diagnostic Aids

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

Electrical Information Reference

DTC Type Reference

ADD LINK

Scan Tool Reference

Engine Control Module Scan Tool Information

Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify DTCs P0122, P0123, P0222, or P0223 are not set.

⇒	If any of the DTCs are set refer to DTC P0120-P0123, P0220, P0222, P0223, or P2135 for further diagnosis.

2. Ignition ON, observe the scan tool TP Sensor percentage parameters with a scan tool. Verify the scan tool TP sensor parameters are between 7-21 percent.

⇒	If not within the specified range, refer to DTC P0120-P0123, P0220, P0222, P0223, or P2135 for further diagnosis.

3. 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, or P2119 should not set.

⇒	If DTCs P0122, P0123, P0222, P0223, or P2135 set while performing this procedure, refer to DTC P0120-P0123, P0220, P0222, P0223, or P2135 for further diagnosis.

4. 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.

⇒	If DTCs P0122, P0123, P0222, P0223, or P2135 set while performing this procedure, refer to DTC P0120-P0123, P0220, P0222, P0223, or P2135 for further diagnosis.

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, 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.

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

2. Disconnect the harness connector at the throttle body.
3. Ignition ON, test for less than 0.5 volt on the motor control 1 circuit terminal A, and motor control 2 circuit terminal B.

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

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

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

5. Connect the test lamp between the motor control 1 circuit terminal A, and motor control 2 circuit terminal B. Observe the test lamp while turning the ignition ON for 5 seconds and then OFF. Verify the test lamp illuminates.

⇒	If the test lamp does not illuminate, test each motor control circuit for an open, or for a short between the motor control 1 and motor control 2 circuits. If the circuit tests normal, 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.