Circuit Description
The control module enables the fuel pump relay when the ignition switch is turned ON. The control module will disable the fuel pump relay within two seconds unless the control module detects ignition reference pulses. The control module continues to enable the fuel pump relay as long as ignition reference pulses are detected. The control module disables the fuel pump relay within 2 seconds if ignition reference pulses cease to be detected and the ignition remains ON.
Fuel Pump Electrical Circuit Diagnosis
| Step | Action | Yes | No |
|---|---|---|---|
| Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Controls Connector End Views or Powertrain Control Module (PCM) Connector End Views |
|||
| 1 | Did you perform the Diagnostic System Check-Engine Controls? | Go to Step 2 | Go toDiagnostic System Check - Engine Controls |
| 2 |
|
Go to Intermittent Conditions | Go to Step 3 |
| 3 | Command the fuel pump relay ON and OFF with a scan tool. Do you hear the fuel pump relay click when you command the fuel pump relay ON and OFF? |
Go to Step 9 | Go to Step 4 |
| 4 |
|
Go to Step 5 | Go to Step 6 |
| 5 |
|
Go to Step 19 | Go to Step 22 |
| 6 | Does the test lamp remain illuminated with each command? | Go to Step 7 | Go to Step 8 |
| 7 | Test the control circuit of the fuel pump relay for a short to voltage. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 27 | Go to Step 26 |
| 8 | Test the control circuit of the fuel pump relay for a short to ground or an open. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 27 | Go to Step 20 |
| 9 | Turn ON the ignition, with the engine OFF. Does the fuel pump operate continuously? |
Go to Step 10 | Go to Step 11 |
| 10 |
|
Go to Step 21 | Go to Step 25 |
| 11 | Inspect the fuel pump fuse. Is the fuel pump fuse open? |
Go to Step 12 | Go to Step 14 |
| 12 |
|
Go to Step 27 | Go to Step 13 |
| 13 |
|
Go to Step 24 | Go to Intermittent Conditions |
| 14 |
|
Go to Step 15 | Go to Step 23 |
| 15 | Connect a 20-amp fused jumper wire between the ignition 1 voltage circuit of the fuel pump relay and the supply voltage circuit of the fuel pump. Does the fuel pump operate? |
Go to Step 19 | Go to Step 16 |
| 16 | Test the supply voltage circuit of the fuel pump for an open or high resistance between the fuel pump relay and the fuel pump. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 27 | Go to Step 17 |
| 17 |
IMPORTANT:
Inspect the ground circuit for correct tightening, corrosion on the terminals, or damage to the wiring harness. Test the ground circuit of the fuel pump for an open or high resistance. Refer to Circuit Testing
and Wiring Repairs
in Wiring Systems.Did you find and correct the condition? |
Go to Step 27 | Go to Step 18 |
| 18 | Test for an intermittent and for a poor connection at the fuel sender cover. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 27 | Go to Step 24 |
| 19 | Test for an intermittent and for a poor connection at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 27 | Go to Step 25 |
| 20 | Test for an intermittent and for a poor connection at the PCM. Refer to Testing for Intermittent Conditions and Poor Connections
and Connector Repairs
in Wiring Systems. Did you find and correct the condition? |
Go to Step 27 | Go to Step 26 |
| 21 | Repair the short to voltage in the supply voltage circuit of the fuel pump. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 27 | - |
| 22 | Repair the open or high resistance in the ground circuit of the fuel pump relay. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 27 | - |
| 23 | Repair the open in the ignition 1 voltage circuit of the fuel pump relay. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
Go to Step 27 | - |
| 24 |
IMPORTANT:
Inspect for poor connections at the fuel pump, within the fuel tank, before replacing the fuel pump.
|
Go to Step 27 | - |
| 25 | Replace the fuel pump relay. Did you complete the replacement? |
Go to Step 27 | - |
| 26 | Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement
. Did you complete the replacement? |
Go to Step 27 | - |
| 27 | Operate the system in order to verify the repair. Did you correct the condition? |
System OK | Go to Step 2 |