2010 Cadillac Truck SRX FWD V6-3.0L Page 1942
Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. Verify DTC P0121, P0122, P0123, P0221, P0222, or P0223 is not set.
瀚慖f a DTC is set refer to DTC P0121-P0123 or P0221-P0223 (Without LF1, LFW) ( See: P Code Charts/P0121) for further diagnosis.
2. Observe the scan tool Throttle Position Sensor voltage parameters. Verify that Throttle Position Sensor 1 voltage is between 3.24-3.54 V, and
Throttle Position Sensor 2 voltage is between 1.36-1.86 V.
瀚慖f either Throttle Position Sensor voltage is not within the specified range refer to DTC P0121-P0123 or P0221-P0223 (Without LF1,
LFW) (See: P Code Charts/P0121) for further diagnosis.
3. Rapidly depress the accelerator pedal from the rest position to the wide open throttle position (WOT) and release the pedal. Repeat the
procedure several times. DTCs P0638, P2100, P2101, P2102, P2103, or P2119 should not set.
瀚慖f a DTC P0121, P0122, P0123, P0221, P0222, or P0223 set while performing this procedure refer to DTC P0121-P0123 or
P0221-P0223 (Without LF1, LFW) (See: P Code Charts/P0121) 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. DTC
P0638, P2100, P2101, P2102, P2103, or P2119 should not set.
瀚慖f a DTC P0121, P0122, P0123, P0221, P0222, or P0223 set while performing this procedure, refer to DTC P0121-P0123 or
P0221-P0223 (Without LF1, LFW) (See: P Code Charts/P0121) 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. Inspect the Q38 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
瀚慖f a condition is found, replace the Q38 throttle body.
Note: Disconnecting the throttle body harness connector causes additional DTCs to set.
2. Ignition OFF, disconnect the harness connector of the Q38 throttle body.
3. Ignition ON, test for 4.0-4.2 V between the TAC motor control 1 circuit terminal B and ground.
瀚慖f voltage is greater than the specified range, test each of the motor control circuits for a short to voltage. If the circuits tests normal,
replace the K20 Engine Control Module.
瀚慖f voltage is less than the specified range, test the motor control 1 circuit for a short to ground or an open/high resistance. If the circuit
tests normal, replace the K20 Engine Control Module.
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 K20 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 K20 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 K20 Engine Control Module.
7. If all circuits test normal, replace the Q38 throttle body.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
