2010 Cadillac CTS Sedan AWD V6-3.0L Page 1531
DTCs P0627, P0628, and P0629 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics (LLT) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)Engine Controls Schematics
(LF1) (See: Diagrams/Electrical Diagrams/Powertrain Management/System Diagram)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/Circuit
Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/Wiring Repairs/Wiring Repairs)
DTC Type Reference
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. Attempt to start the engine. Observe the DTC information with a scan tool. DTC P0627, P0628, or P0629 should not set.
2. Ignition ON, command the fuel pump ON and OFF with a scan tool while observing the following control circuit status parameters:
* Fuel Pump Enable Circuit Low Voltage Test Status
* Fuel Pump Enable Circuit Open Test Status
* Fuel Pump Enable Circuit High Voltage Test Status
Each parameter should toggle between OK and Not Run or Not Run and OK.
3. 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 K27 fuel pump control module harness connector.
2. Connect a test lamp between the enable circuit terminal 13 of the fuel pump control module and ground.
3. Ignition ON, command the fuel pump ON and OFF with a scan tool. The test lamp should turn ON and OFF as commanded.
瀚慖f the test lamp remains OFF all the time, test for a short to ground or an open/high resistance on the enable circuit. If circuit/connections
test normal, replace the K20 ECM.
瀚慖f the test lamp remains ON all the time, test for a short to voltage on the enable circuit. If circuit/connections test normal, replace the K20
ECM.
4. Ignition ON, test for 2-3 V on the enable circuit terminal 13 of the fuel pump control module.
瀚慖f not within the specified range, replace the K20 ECM.
5. If all circuits/connections test normal, replace the K27 fuel pump control module.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
Control Module References (See: Testing and Inspection/Programming and Relearning) for ECM or fuel pump control module replacement, setup,
and programming
P0628
DTC P0627-P0629 (w/LF1)
Diagnostic Instructions
