P0748 Diagnostic Trouble Code

P0748 is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a P0748 diagnostic trouble code may include:

Malfunction Indicator Lamp (MIL) illuminated
Carbon Buildup on O2 Sensor
Poor fuel economy
Rich or lean exhaust

Possible Causes :

The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Fuel with a large percentage of sulfur will clog the DPF quickly
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.

Repair Processes :

Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications.

Process Tips

Diagnostic trouble code P0748 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before P0748.

Fortunately, P0748 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P0748 Trouble Code For Specific Cars

P0748 Mercedes Clk 240 ABS Outlet Valve Coil LR Circuit Open
P0748 Lamborghini Jalpa Signal Link Fault (Non SCP)
P0748 Rover 3-litre Ignition Coil A Primary/Secondary Circuit Malfunction
P0748 Voisin C Random/Multiple Cylinder Misfire Detected
P0748 Lancia Lambda Speed Wheel Sensor RR Input Circuit Failure
P0748 Citroen Visa Fuel Rail Pressure Sensor Circuit High Input
P0748 Jeep Willys Seat Driver Recline Forward Circuit Failure