Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Test HC: Gasoline Fuel Delivery System: Testing
| Fault Code | KOEO | KOER | Continuous Memory |
|---|---|---|---|
| P0148 | HC1 |
- 1) For Continuous Memory Only DTC P0148: Check System Integrity
This DTC indicates at least one bank lean at wide open throttle. Possible causes are:- Severely restricted fuel filter.
- Severely restricted fuel supply line.
Visually inspect complete fuel delivery system for damage. Check fuel lines, connections, relays, fuel tank, fuel pump, fuel pressure regulator, fuel pulse damper and fuel injector areas for leaks. Check for looseness, cracks, kinks, pinching, or abrasion caused by a collision or mishandling. Visually inspect electrical harness and connectors for loose pins, corrosion, abrasion, or other damage from collision or mishandling. Check electrical connectors for proper mating. Ensure customer has followed vehicle maintenance schedule. Ensure Inertia Fuel Shutoff (IFS) switch is reset. Ensure battery is fully charged (12.5 volts or more) and that fuses are okay. Ensure fuel level in tank is sufficient. Repair as necessary. If no faults are found, go to next step.
- 2) Check Voltage At Fuel Pump Harness Connector
Connect battery charger to battery. Ensure IFS is reset. If it is not reset, perform INERTIA FUEL SHUTOFF SWITCH RESET PROCEDURE under GASOLINE SYSTEM under FUEL SYSTEM SAFETY PRECAUTIONS. Connect scan tool to Data Link Connector (DLC). Disconnect fuel pump harness connector at fuel pump. Turn ignition switch to ON position. Connect DVOM between fuel pump PWR and GND circuits at fuel pump harness connector. See WIRING DIAGRAMS . Using scan tool, access OUTPUT TEST MODE. See OUTPUT TEST MODE under ADDITIONAL SYSTEM FUNCTIONS. Command fuel pump ON and monitor DVOM voltage. If voltage is more than 12.5 volts, turn ignition switch to OFF position, exit OUTPUT TEST MODE, reconnect fuel pump harness connector and go to next step. If voltage is 12.5 volts or less, go to TEST KB, step 70) (ERFS vehicles), or check for open or shorts in fuel pump PWR or GND circuits (all others). See Figure. - 3) Check Fuel Filter For Proper Maintenance
Check last time fuel filter was replaced. If fuel filter has been serviced regularly (within 30,000 miles), go to next step. If fuel filter has not been serviced regularly, replace fuel filter and go to next step.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.