P0627
DTC P0627-P0629
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC P0627
- Fuel Pump Enable Circuit
DTC P0628
- Fuel Pump Enable Circuit Low Voltage
DTC P0629
- Fuel Pump Enable Circuit High Voltage
Diagnostic Fault Information
Circuit/System Description
The engine control module (ECM) provides ignition voltage to the fuel pump flow control module whenever the engine is cranking or running. The control module enables the fuel pump flow control module as long as the engine is cranking or running, and ignition system reference pulses are received. While this enable voltage is being received, the fuel pump flow control module supplies a varying voltage to the in-tank fuel pump module in order to maintain the desired fuel line pressure.
Conditions for Running the DTC
P0627 and P0629
* The ignition voltage is 11 V or greater.
* The ECM has commanded the fuel pump OFF.
* The DTCs run continuously when the above conditions are met for greater than 1 s.
P0628
* The ignition voltage is 11 V or greater.
* The ECM has commanded the fuel pump ON.
* The DTC runs continuously when the above conditions are met for greater than 1 s.
Conditions for Setting the DTC
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 2 s.
Action Taken When the DTC Sets
DTCs P0627, P0628, and P0629 are Type B DTCs.
Conditions for Clearing the DTC
DTCs P0627, P0628, and P0629 are Type B DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views Sunshade - Left (D61)
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify that DTC P0627, P0628, or P0629 is not set.
• If a DTC is set
Refer to Circuit/System Testing.
• If a DTC is not set
3. Verify the parameters listed below do not display Malfunction when commanding the Fuel Pump Enable On and Off with a scan tool.
* Fuel Pump Enable Circuit Low Voltage Test Status
* Fuel Pump Enable Circuit Open Test Status
* Fuel Pump Enable Circuit High Voltage Test Status
• If Malfunction is displayed
Refer to Circuit/System Testing.
• If Malfunction is not displayed
4. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
5. Verify the DTC does not set.
• If the DTC sets
Refer to Circuit/System Testing.
• If the DTC does not set
6. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the K27 Fuel Pump Control Module.
2. Ignition ON for 10 s.
3. Verify that a test lamp does not illuminate between the control circuit terminal 20 and ground.
• If the test lamp illuminates
1. Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
2. Test for less than 1 V between the control circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K20 Engine Control Module.
• If the test lamp does not illuminate
4. Remove the test lamp.
5. Verify the scan tool Fuel Pump Enable Circuit Low Voltage Test Status parameter is OK when commanding the Fuel Pump Enable On with a scan tool.
• If OK is not displayed
1. Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance, replace the K20 Engine Control Module.
• If OK is displayed
6. Install a 3 A fused jumper wire between the control circuit terminal 20 and ground.
7. Verify the scan tool Fuel Pump Enable Circuit Low Voltage Test Status parameter is Malfunction when commanding the Fuel Pump Enable On with a scan tool.
• If Malfunction is not displayed
1. Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
2. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K20 Engine Control Module.
• If Malfunction is displayed
8. Replace the K27 Fuel Pump Control Module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
Control Module References Control Module References for Engine Control Module or Fuel Pump Flow Control Module replacement, programming, and setup