2010 Cadillac CTS Sedan AWD V6-3.6L Page 791
1. Observe the DTC information with a scan tool. DTC P0627, P0628, P0629, P069E, or U0109 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. Attempt to start and idle the engine.
3. Observe the DTC information with a scan tool. DTCs P0089, P00C6, P228C, and P228D should not set.
4. 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).
5. 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 commanded state.
6. 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
Note: Circuit/System Verification must be performed first or misdiagnosis may result.
1. Ignition ON, observe the scan tool fuel pump control module fuel line pressure sensor parameter. Command an increase in the fuel line
pressure with a scan tool. Verify the fuel line pressure increases to greater than 414 kPa (60 psi) as commanded.
瀚慖f less than the specified range, refer to Fuel System Diagnosis (See: Powertrain Management/Computers and Control Systems/Testing
and Inspection/Component Tests and General Diagnostics/Fuel System Diagnosis).
Note: As little as 2 ohm on either circuit of the high pressure fuel pump actuator will cause these DTCs to set. Test the circuits of the high
pressure fuel pump actuator for a high resistance if you suspect a condition.
2. Remove the G18 high pressure fuel pump and visually inspect the lobes on the camshaft for unusual wear.
瀚慖f the lobes appear normal, replace the G18 high pressure fuel pump.
瀚慖f the lobes are worn, replace the camshaft.
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 10 ohm plus/minus 1 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. Test for infinite resistance between each terminal and the G18 high pressure fuel pump housing.
瀚慖f not the specified value, replace the G18 high pressure fuel pump.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Camshaft Replacement - Right Side (LP1, LY7) (See: Engine, Cooling and Exhaust/Engine/Camshaft, Lifters and Push
Rods/Camshaft/Service and Repair/Camshaft Replacement - Right Side)
* Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LF1) (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel
Pressure Sensor/Switch/Service and Repair)Fuel Pressure Sensor Replacement - Fuel Injection Fuel Rail (LLT) (See: Powertrain
Management/Fuel Delivery and Air Induction/Fuel Pressure Sensor/Switch/Service and Repair)
* Fuel Pump Replacement (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Pump/Service and Repair)
P00C8
DTC P0090-P0092, P00C8, P00C9, or P00CA (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.
