P0748: Pressure Control Solenoid A Electrical
What to do
The transmission has probably defaulted to a protective mode with fixed pressure, so shifts will be harsh or it will hold one gear. Drive it gently to a garage rather than any distance — the converter is unlocked in that state and heats the fluid.
What this code means
A measurable electrical fault in the pressure control solenoid circuit — winding resistance outside specification, an open circuit, or a short. Because this solenoid is current-controlled rather than simply switched, the module monitors the current it is actually drawing against what it commanded, which makes it unusually good at detecting a partially failed winding rather than only a completely dead one.
The consequence is that P0748 can appear while the transmission still broadly works, catching a solenoid on its way out. That is a better position than the alternative, and worth acting on rather than clearing.
On a shared driver stage, one shorted solenoid can pull down the supply to others — so if codes for several solenoids appear together, measure each winding individually before concluding the module has failed.
Likely causes
Start here
- Faulty pressure control solenoid · moderate
- Short circuit in a transmission solenoid · moderate
- Fluid tracking into the transmission connector · moderate
Less common
- Damaged transmission wiring harness · moderate
Rare
- Faulty transmission control module · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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