Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Fuel System Description (See: Powertrain Management/Computers and Control Systems/Description and Operation/Fuel System Description)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/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 Testing
1. Verify that DTCs P018C, P018D, P0231, P0232, or P023F are not set.
锟斤拷If the DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle (See: Diagnostic Trouble Code Descriptions/Diagnostic
Trouble Code (DTC) List - Vehicle).
2. Ignition OFF, disconnect the harness connector at the G12 fuel pump.
3. Ignition OFF, test for less than 5.0 ohm between the G12 fuel pump low reference circuit terminal A and ground.
锟斤拷If greater than the specified range, test the G12 fuel pump low reference circuit for a high resistance. If the circuit tests normal, replace
the K27 fuel pump control module.
4. Ignition OFF, install a test lamp between the control circuit terminal D and the low reference circuit terminal A.
5. Ignition ON, command the Fuel Pump Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between
the commanded states.
锟斤拷If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K27 fuel pump control
module.
锟斤拷If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace
the K27 fuel pump control module.
6. Perform the Fuel System Diagnosis (w/o FPCM) (See: Powertrain Management/Computers and Control Systems/Testing and
Inspection/Component Tests and General Diagnostics)Fuel System Diagnosis (FPCM) (See: Powertrain Management/Computers and
Control Systems/Testing and Inspection/Component Tests and General Diagnostics) to verify proper fuel pressure.
锟斤拷If the fuel pressure is not normal, replace the G12 fuel pump
7. If all circuits test normal, replace the K27 fuel pump control module.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Fuel Tank Fuel Pump Module Replacement (2500 LWB - 43.5L (11.5 gal) Tank Rear) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Pump/Service and Repair/Fuel Tank Fuel Pump Module Replacement (2500 LWB - 43.5L (11.5 Gal) Tank Rear))Fuel Tank
Fuel Pump Module Replacement (2500 LWB - 98.4L (26 gal) Tank Front) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Pump/Service and Repair/Fuel Tank Fuel Pump Module Replacement (2500 LWB - 98.4L (26 Gal) Tank Front))Fuel Tank
Fuel Pump Module Replacement (1500 SWB - 98.4L (26 gal) Tank + E85) (See: Powertrain Management/Fuel Delivery and Air
Induction/Fuel Pump/Service and Repair/Fuel Tank Fuel Pump Module Replacement (1500 SWB - 98.4L (26 Gal) Tank + E85))Fuel Tank
Fuel Pump Module Replacement (1500 Series) (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Pump/Service and
Repair/Fuel Tank Fuel Pump Module Replacement (1500 Series))Fuel Tank Fuel Pump Module Replacement (1500 LWB - 117.3L (31 gal)
Tank + E85) (See: Powertrain Management/Fuel Delivery and Air Induction/Fuel Pump/Service and Repair/Fuel Tank Fuel Pump Module
Replacement (1500 LWB - 117.3L (31 Gal) Tank + E85))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for fuel pump control module replacement, setup,
