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Diagnostic Procedure

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P0627-FUEL PUMP RELAY CIRCUIT DIAGNOSTIC TEST REFERENCE

TEST ACTION APPLICABILITY
1 Ignition on, engine not running.
With the DRBIII®, actuate the Fuel Pump Relay.
Is the Fuel Pump Relay operating?
Yes --> Refer to the INTERMITTENT CONDITION SYMPTOM .
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
No --> Go To 2
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2 Turn the ignition off.
Remove the Fuel Pump Relay from the PDC.
Ignition on, engine not running.
Using a 12-volt test light connected to ground, probe the (F1) Fused Ignition Switch Output circuit in the PDC.
Does the test light illuminate brightly?
Yes --> Go To 3
No --> Repair the (F1) Fused Ignition Switch Output circuit. Inspect the related fuse. An open fuse may have been caused by a short to ground.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
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3 Turn the ignition off.
Using a 12-volt test light connected to ground, probe the (A209) Fused B+ circuit of the fuel pump relay in the PDC.
Does the test light illuminate brightly?
Yes --> Go To 4
No --> Repair the open or short to ground in the (A209) Fused B+ circuit. Inspect and replace any open fuses.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
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4 Measure the resistance of the Fuel Pump Relay Coil.
Is the resistance between 70 to 90 ohms?
Yes --> Go To 5
No --> Replace the Fuel Pump Relay.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
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5 Disconnect the C3 PCM harness connector.
CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Measure the resistance of the (K31) Fuel Pump Relay Control circuit from the PDC to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes --> Go To 6
No --> Repair the open in the (K31) Fuel Pump Relay Control circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
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6 Measure the resistance between ground and the (K31) Fuel Pump Relay Control circuit in the PDC.
Is the resistance below 5.0 ohms?
Yes --> Repair the short to ground in the (K31) Fuel Pump Relay Control circuit.
Perform POWERTRAIN VERIFICATION TEST VER - 5 .
No --> Go To 7
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7
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.If there are no possible causes remaining, view repair.RepairReplace and program the Powertrain Control Module per Service Information.Perform POWERTRAIN VERIFICATION TEST VER - 5 .
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