P0603 Diagnostic Trouble Code

P0603 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 P0603 diagnostic trouble code may include:

Faulty PCM
The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.
Poor acceleration
Hesitation upon acceleration

Possible Causes :

Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
A large air leak at or near the number one oxygen sensor would also cause a lean mixture.

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. Check to make sure they are not burnt or corroded. If in doubt, get some Electrical Contact cleaner at any parts store if cleaning of the terminals is needed.

Process Tips

Diagnostic trouble code P0603 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 P0603.

Fortunately, P0603 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P0603 Trouble Code For Specific Cars

P0603 Mercury Mountaineer Ii Air Suspension Rear Inflator Solenoid Output Circuit Failure
P0603 Mazda Mx-3 1-2 Shift Malfunction
P0603 Chevrolet Triax Engine Coolant Level Switch Circuit Failure, GEM
P0603 Lagonda 2-litre Shift Solenoid D Electrical
P0603 Fageol Fageol Injector Circuit Malfunction - Cylinder 10
P0603 Talbot 150 Mirror Passenger Down Circuit Short To Ground
P0603 Vauxhall Nova Pressure Control Solenoid B Performance