2010 Cadillac CTS Sedan AWD V6-3.0L Page 1897
* 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
瀚慖f a condition is found, replace the throttle body assembly.
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, verify that a test lamp does not illuminate between each control circuit listed below and ground.
* TAC Motor Control Closed circuit terminal A
* TAC Motor Control Open circuit terminal B
瀚慖f test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
4. Ignition ON, verify that a test lamp does not illuminate between each control circuit listed below and B+.
* TAC Motor Control Closed circuit terminal A
* TAC Motor Control Open circuit terminal B
瀚慖f the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the ECM.
5. Ignition 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 or a lower voltage will be
recorded.
* The ignition must be OFF and the ECM completely powered down before testing each circuit or a lower voltage will be recorded.
6. Ignition OFF, measure the voltage using the DMM Min/Max Recording Mode function on each circuit listed below as the ignition is turned
ON. The Max voltage should be within 1 V of B+.
* TAC Motor Control Closed circuit terminal A
* TAC Motor Control Open circuit terminal B
瀚慖f not within the specified range, test the circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
7. If all circuits and connections test normal, replace the throttle body assembly.
Repair Instructions
* Throttle Body Assembly Replacement (LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Throttle Body/Service and
Repair/Removal and Replacement)Throttle Body Assembly Replacement (LLT) (See: Powertrain Management/Fuel Delivery and Air
Induction/Throttle Body/Service and Repair/Removal and Replacement)
* Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM replacement, setup, and programming
Repair Verification
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. Turn OFF the ignition for 60 seconds.
Note: If the Throttle Sweep Test is not available on the scan tool, use the accelerator to perform the test. Refer to Diagnostic Aids for further
details.
5. Perform the Throttle Sweep Test while observing the TAC Motor parameter with a scan tool. The TAC Motor parameter should display
Enabled while the Throttle Sweep Test is in progress.
6. 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 the DTC resets or another DTC is present, refer to the Diagnostic Trouble Code (DTC) List -
Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble Code (DTC) List - Vehicle) and perform the appropriate diagnostic
procedure.
P2177
DTC P2177, P2179, P2187, or P2189 (w/LLT)
Diagnostic Instructions
