Fuel Pump and Its Circuit Check: Troubleshooting
NOTE:
- Before troubleshooting, be sure to read PRECAUTIONS FOR ECM CIRCUIT INSPECTION .
- When measuring circuit voltage and/or pulse signal at ECM connector, connect special tool to ECM and ECM connectors.
TROUBLESHOOTING CHART
| Step | Action | YES | NO |
|---|---|---|---|
| 1 | Fuel pump control system check for operation
Is it in good condition? |
Fuel pump circuit is in good condition. | Go to Step 2. |
| 2 | Fuel pump relay power supply check
Is it in good condition? |
Go to Step 3. | Repair or replace fuel pump relay power supply circuit. |
| 3 | Fuel pump relay check
Is relay in good condition? |
Go to Step 4. | Replace fuel pump relay. |
| 4 | Fuel pump relay drive circuit check
Are they in good condition? |
Go to Step 5. | Repair or replace fuel pump relay drive circuit. |
| 5 | Fuel pump relay drive signal check
Is it in good condition? |
Go to Step 6. | Substitute a known-good ECM and recheck. |
| 6 | Fuel pump power supply circuit check
Is it in good condition? |
Go to Step 7. | Repair or replace fuel pump power supply circuit. |
| 7 | Fuel pump power supply circuit check
Is it in good condition? |
Go to Step 8. | Repair or replace fuel pump power supply circuit. |
| 8 | Fuel pump ground circuit check
Is it in good condition? |
Replace fuel pump. | Repair or replace fuel pump ground circuit. |