DTC P0627-P0629
DTC P0627-P0629 |
Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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DTC Descriptors |
DTC P0627 00
Fuel Pump Relay Control Circuit Open
DTC P0628 00
Fuel Pump Relay Control Circuit Low Voltage
DTC P0629 00
Fuel Pump Relay Control Circuit High Voltage
Diagnostic Fault Information |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
Relay Coil Control
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P0628 00
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P0627 00
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P0629 00
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-
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Relay Coil Ground
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-
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-
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-
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-
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Circuit/System Description |
The engine control module (ECM) provides ignition voltage to the coil side of the fuel pump relay whenever the engine is cranking or running. The ECM enables the fuel pump relay as long as the engine is cranking or running, and ignition system reference pulses are received. If no ignition system reference pulses are received, the ECM turns OFF the fuel pump. The fuel pump's relay control circuit is equipped with a feedback circuit that receives voltage within the ECM. By monitoring the voltage in the feedback circuit the ECM can determine whether the control circuit is open, short-circuited to ground or short-circuited to a voltage.
Conditions for Running the DTC |
P0627 00 and P0628 00
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The ignition is ON.
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The power stage is not active.
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The DTCs run continuously when the above conditions are met.
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P0629 00
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The ignition is ON or the engine is running.
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The power stage is active.
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The DTCs run continuously when the above conditions are met.
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Conditions for Setting the DTC |
P0627 00
The ECM detects the fuel pump relay control circuit is open for greater than 1 s.P0628 00
The ECM detects the fuel pump relay control circuit is shorted to ground for greater than 1 s.P0629 00
The ECM detects the fuel pump relay control circuit is shorted to battery for greater than 1 s.Action Taken When the DTC Sets |
DTC P0627, P0628 and P0629 are Type A DTCs.
Conditions for Clearing the DTC |
DTC P0627, P0628 and P0629 are Type A DTCs.
Reference Information |
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References
Circuit/System Verification |
1. |
Ignition ON, command the Fuel Pump Relay ON and OFF with a scan tool. You should hear and feel an audible click.
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2. |
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.
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Circuit/System Testing |
1. |
Ignition OFF, disconnect the KR23A Fuel Pump Relay.
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2. |
Test for less than 5 Ω between the ground circuit terminal 85 and ground.
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3. |
If greater than the specified range, test the ground circuit for an open/high resistance.
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4. |
Connect a test lamp between the control circuit terminal 86 and ground.
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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.
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6. |
If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K20 Engine Control Module.
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7. |
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 K20 Engine Control Module.
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8. |
If all circuits test normal, test or replace the KR23A Fuel Pump Relay.
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Component Testing |
Relay Test
1. |
Ignition OFF, disconnect the fuel pump relay.
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2. |
Test for 70-110 Ω between terminals 85 and 86.
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3. |
If not within the specified range, replace the KR23A Fuel Pump Relay
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4. |
Test for infinite resistance between the following terminals:
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30 and 86
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30 and 87
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30 and 85
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85 and 87
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5. |
If not the specified value, replace the KR23A Fuel Pump Relay.
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6. |
Install a 20 A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.
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7. |
If greater than the specified range, replace the KR23A Fuel Pump Relay.
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Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Relay Replacement (Attached to Wire Harness)
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Control Module References
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