P0748 means Pressure Control Solenoid A Electrical. There is an electrical fault in the circuit of pressure control solenoid A, which sets line pressure. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0748 means
Electronically controlled automatics are run by a transmission control module (TCM), a separate box or part of the engine computer. It reads speed sensors, the range sensor and fluid temperature to decide when to shift, and drives solenoids that apply clutches and the torque converter clutch. Many basic code readers only show the generic P0700; a scan tool that reads the transmission module shows the specific fault. Check fluid level and condition first, since low or burnt fluid causes many transmission codes.
P0748 symptoms
- Very harsh or very soft shifts
- Limp mode
- Slipping
Common causes of P0748
- Failed pressure control solenoid
- Internal harness or connector fault
- TCM driver fault
How to diagnose P0748
- Check solenoid resistance at the case connector
- Inspect the harness and connector
- Check transmission fluid level and condition first
Can you drive with P0748?
Limit driving; wrong line pressure damages clutches.
P0748 tips
Pressure control solenoid faults change line pressure, which affects every shift. Fix them promptly, because low line pressure lets clutches slip and burn.
Will P0748 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0748 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0776 | Pressure Control Solenoid B Performance or Stuck Off |
| P0868 | Transmission Fluid Pressure Low |
| P0700 | Transmission Control System Malfunction |
Guides that help
- transmission shifting hard
- transmission solenoid symptoms
- 4L60E shift solenoids
- transmission slipping
When it is more than a sensor
If the fault turns out to be internal (worn clutches, a failed converter or a damaged valve body), compare a rebuild with a replacement in transmission rebuild vs replacement and transmission replacement cost, identify your unit with what transmission do I have?, and browse our transmissions.
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