2010 Cadillac CTS Sedan AWD V6-3.6L Page 788
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Diagnostic Trouble Code Descriptions/Powertrain Diagnostic Trouble Code
(DTC) Type Definitions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
1. Observe the DTC information with a scan tool. DTC P0090, P0091, P0092, P00C8, P00C9, P00CA, P0685, or P1682 should not set.
瀚慖f a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic Trouble
Code (DTC) List - Vehicle).
2. Ignition ON, command the Fuel Pressure Regulator ON and OFF with a scan tool while observing the following control circuit status
parameters:
* Fuel Pressure Regulator Control Circuit High Voltage Test Status
* Fuel Pressure Regulator Control Circuit Open Test Status
* Fuel Pressure Regulator Control Circuit Low Voltage Test Status
* Fuel Pressure Regulator High Control Circuit High Voltage Test Status
* Fuel Pressure Regulator High Control Circuit Open Test Status
* Fuel Pressure Regulator High Control Circuit Low Voltage Test Status
Each parameter should toggle between OK and Not Run or Not Run and OK.
3. Engine idling, observe the Fuel Rail Pressure Sensor parameter with a scan tool. The pressure should be approximately 1.9-2.1 MPa (279-305
psi).
4. Command an increase and decrease in fuel rail pressure with a scan tool. Observe the scan tool Fuel Rail Pressure Sensor parameter. The
Fuel Rail Pressure Sensor should increase or decrease with each command.
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, disconnect the harness connector at the G18 high pressure fuel pump.
2. Ignition OFF, verify that a test lamp does not illuminate between B+ and the low control circuit terminal 1.
瀚慖f the test lamp illuminates, test the low control circuit for a short to ground. If the circuit tests normal, replace the K20 ECM.
3. Ignition ON, verify that a test lamp does not illuminate between ground and the high control circuit terminal 2.
瀚慖f the test lamp illuminates, test the high control circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
4. Ignition ON, command the Fuel Pressure Regulator ON with a scan tool. Verify that the test lamp illuminates.
瀚慖f the test lamp does not illuminate, test the high control circuit for a short to ground or an open/high resistance. If the circuit tests normal,
replace the K20 ECM.
5. Ignition OFF, connect a test lamp between the low control circuit terminal 1 and B+.
6. Ignition ON, command the Fuel Pressure Regulator ON with a scan tool. Verify that the test lamp illuminates.
瀚慖f the test lamp does not illuminate, test the low control circuit for a short to voltage or an open/high resistance. If the circuit tests normal,
replace the K20 ECM.
7. If all circuits test normal, test or replace the G18 high pressure fuel pump.
Component Testing
Static Test
1. Ignition OFF, disconnect the harness connector at the G18 high pressure fuel pump.
Note: The DMM and test leads must be calibrated to 0 ohm in order to prevent misdiagnosis.
2. Test for 9-11 ohm at 25掳C (77掳F) between the low control circuit terminal 1 and the high control circuit terminal 2.
瀚慖f not within the specified range, replace the G18 high pressure fuel pump.
3. Measure the resistance between each terminal and the high pressure fuel pump housing. The DMM should display OL.
瀚慖f less than the specified value, replace the G18 high pressure fuel pump.
