P0748 ISUZU - Faulty Transmission Pressure Control Solenoid
- Faulty line pressure solenoid valve
- Line pressure solenoid valve harness is open or shorted
- Line pressure solenoid valve circuit poor electrical connection
- Low transmission fluid level
- Dirty transmission fluid
When a transmission solenoid is malfunctioned, in most cases the problem is not the electrical part of the solenoid; the problem is foreign material obstructing the mechanical function of the solenoid or the flow of the fluid through the transmission valve body. If the transmission fluid is dirty, it's recommended to change the transmission fluid and if possible removing the transmission pan for further diagnosis. Excessive debris or metal particles on the transmission pan could be an indication that there is a mechanical transmission failure and that the transmission will need to be rebuilt or replaced.
When is the code detected?
Engine Control Module (ECM) detectes an open or shorted condition on the solenoid circuit
- Engine Light ON (or Service Engine Soon Warning Light)
- Transmission shift shock
P0748 Isuzu Description
The Pressure Control (PC) Solenoid Valve an electronic pressure regulator that controls transmission line pressure based on current flow through its coil windings. As current flow is increased, the magnetic field produced by the coil moves the solenoid’s plunger further away from the exhaust port. Opening the exhaust port decreases the output fluid pressure regulated by the PC solenoid valve, which ultimately decreases line pressure. The line pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in response to a signal sent from the Transmission Control Module (TCM).