Volt

DTC P1516, P2101, P2119, or P2176

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.

P1516

P2101

P2119

P2176

P1516

The actual throttle position does not match the predicted throttle position for greater than 1 s.

P2101

The actual throttle position does not match the predicted throttle position for greater than 1 s.

P2119

The ECM detects that the throttle blade did not return to the default position when the TAC motor is de-energised for greater than 1 s.

P2176

The ECM detects that both throttle position (TP) sensors were greater than a predetermined voltage during the minimum throttle learn procedure for greater than 2 s.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Hybrid Modes of Operation Description

Throttle Actuator Control (TAC) System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Note: A low 12 V battery voltage or charging system condition may cause a DTC to set.

1. Vehicle in Service Mode.
2. Verify DTC P0121, P0122, P0123, P0222, P0223, P0562, P0563, or P2135 is not set.

⇒	If any of the DTCs are set

Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

⇓	If none of the DTCs are set

3. Verify the scan tool Throttle Body Idle Air Flow Compensation parameter is less than 90 %.

⇒	90 % or greater

Refer to Throttle Body Inspection and Cleaning

⇓	If less than 90 %

4. Clear the DTCs with a scan tool.
5. Vehicle OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
6. Vehicle in Service Mode.
7. Verify the scan tool TAC Motor parameter displays Enabled.

⇒	If Disabled

Refer to Circuit/System Testing

⇓	If Enabled

8. Verify DTC P1516, P2101, P2119, or P2176 is not set.

⇒	If any of the DTCs are set

Refer to Circuit/System Testing

⇓	If none of the DTCs are set

Note: If there is a condition with the throttle body, the TAC Motor Command parameter will go to 99 % for a predetermined amount of time and then a DTC sets. Once a DTC is set, the TAC Motor Command parameter will go to 0 % and the TAC Motor parameter will display Disabled.

9. Verify the scan tool TAC Motor parameter displays Enabled while performing the Throttle Sweep Test with a scan tool.

⇒	If Disabled

Note: Before replacing the throttle body assembly, make sure the TAC motor control circuits are not shorted to B+.

⇒	Test or replace the Q38 throttle body assembly.

⇓	If Enabled

10. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
11. Verify a DTC does not set.

⇒	If any DTC sets

Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

⇓	If no DTCs set

12. All OK

1. Vehicle OFF.

Warning: Turn OFF the ignition before inserting fingers into the throttle bore. Unexpected movement of the throttle blade could cause personal injury.

2. Verify the conditions listed below do not exist with the Q38 throttle body assembly:

•	A throttle blade that is not in the rest position

•	A throttle blade that is binding open or closed

•	A throttle blade that is free to move open or closed without spring pressure

⇒	If a condition is found

Test or replace the Q38 throttle body assembly.

⇓	If a condition is not found

3. Vehicle OFF.

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

4. Disconnect the harness connector at the Q38 throttle body assembly, vehicle in Service Mode.
5. Verify that a test lamp does not illuminate between each motor control circuit listed below and ground.

•	TAC Motor Control Closed circuit terminal A

•	TAC Motor Control Open circuit terminal B

⇒	If the test lamp illuminates

5.1.	Vehicle OFF, disconnect the harness connector at the K20 engine control module, vehicle in Service Mode.

5.2.	Test for less than 1 V between the control circuit and ground.

⇒	If 1 V or greater, repair the short to voltage on the circuit.

⇓	If the test lamp is always OFF

6. Verify that a test lamp does not illuminate between each motor control circuit listed below and B+.

•	TAC Motor Control Closed circuit terminal A

•	TAC Motor Control Open circuit terminal B

⇒	If the test lamp illuminates

6.1.	Vehicle OFF, disconnect the harness connector at the K20 engine control module.

6.2.	Test for infinite resistance between the control circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇒	If infinite resistance, replace the K20 engine control module.

⇓	If the test lamp is always OFF

7. Vehicle OFF, set the DMM to the 40 V scale, select the Min/Max Recording Mode, and set the Peak Min/Max response time to 1 ms.

Note: 

•	The DMM Min/Max Recording Mode and the response time of 1 ms must be reset after testing each circuit.

•	The vehicle must be OFF and the ECM completely powered down before testing each circuit.

8. Verify the Max voltage is within 1 V of B+ while using DMM Min/Max Recording Mode function on each control circuit listed below with the vehicle in Service Mode.

•	TAC Motor Control Closed circuit terminal A

•	TAC Motor Control Open circuit terminal B

⇒	If not within 1 V of B+

8.1.	Vehicle OFF, disconnect the harness connector at the K20 engine control module.

8.2.	Test for less than 2 Ω in the control circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K20 engine control module.

⇓	If within 1 V of B+

9. Test or replace the Q38 throttle body assembly.

1. Install any components that have been removed or replaced during diagnosis.
2. Perform any adjustments, programming or setup procedures that are required when a component is removed or replaced.
3. Clear the DTCs with a scan tool.
4. Vehicle OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
5. Vehicle in Service Mode.
6. Verify the scan tool TAC Motor parameter displays Enabled while performing the Throttle Sweep Test with a scan tool.

⇒	If Disabled

Test or replace the Q38 throttle body assembly.

⇓	If Enabled

7. If the repair was related to a DTC, duplicate the Conditions for Running the DTC and use the Freeze Frame/Failure Records, if applicable, in order to verify the DTC does not reset.

⇒	If any DTC sets

Refer to Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

⇓	If no DTC sets

8. All OK