2010 Cadillac CTS Sedan AWD V6-3.6L Page 1845
4. Connect a test lamp between the TAC motor control 2 circuit terminal A and B+. The test lamp should NOT illuminate.
瀚慖f the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the engine control module.
5. Test for greater than 3.5 V between TAC motor control 1 circuit terminal B and TAC motor control 2 circuit terminal A.
瀚慖f the voltage is less than the specified value, test the motor control 2 circuit for an open/high resistance. If the circuit tests normal,
replace the engine control module.
6. Ignition OFF, connect the EL 34730-405 - Injector Test Lamp between the TAC motor control 1 circuit terminal B and TAC motor control 2
circuit terminal A of the throttle body harness connector. Observe the injector test lamp while turning the ignition ON for 5 s and then OFF.
Verify the injector test lamp illuminates brightly and then turns OFF.
瀚慖f the injector test lamp does not illuminate, replace the engine control module.
7. If all circuits test normal, replace the throttle body.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* 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 engine control module replacement, setup, and
programming
P2101
DTC P0638, P2100, P2101, or P2119 (Without LF1)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provides an overview of each diagnostic category.
DTC Descriptors
DTC P0638
- Throttle Actuator Control (TAC) Command Performance
DTC P2100
- Throttle Actuator Control (TAC) Motor Control Circuit
DTC P2101
- Throttle Actuator Position Performance
DTC P2119
- Throttle Closed Position Performance
Diagnostic Fault Information
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 sensors 1 and
2 to determine the actual throttle valve position.
Conditions for Running the DTCs
