Transmission

P0748 — Pressure Control Solenoid Circuit Electrical Fault

Severity: medium Drive with care, to a shop

What P0748 means

The pressure control solenoid regulates hydraulic line pressure inside the automatic transmission, which determines how smoothly and firmly it shifts. The engine or transmission control module monitors the electrical circuit of this solenoid. P0748 is set when resistance or voltage in the circuit is out of range, pointing to an open, a short, or a failed solenoid.

Symptoms

  • Transmission warning light or Check Engine light on
  • Transmission in limp mode
  • Harsh or banging shifts
  • Delayed or missing shifts
  • Slipping gears
  • Reduced fuel economy

Possible causes

  1. Open in the solenoid circuit
  2. Failed pressure control solenoid
  3. Damaged internal transmission wiring
  4. Corroded or damaged connector or harness
  5. Broken or shorted wiring to the solenoid
  6. Faulty ECM/PCM or TCM

How to diagnose

  1. Scan all codes and freeze frame data and look for other transmission codes
  2. Check transmission fluid level and condition
  3. Inspect the transmission connector and harness for damage, moisture and corrosion
  4. Measure solenoid resistance and compare it with the factory spec
  5. Test the circuit from the connector to the control module for opens and shorts to ground or power
  6. Verify power and ground at the control module
  7. Drop the pan and inspect the internal harness and solenoid connector
  8. If wiring and solenoid are good, test or replace the TCM/PCM

Common fixes

  • Repair the damaged wiring or replace the connector
  • Replace the pressure control solenoid
  • Replace the internal transmission wiring harness
  • Change fluid and filter if contaminated
  • Replace or reprogram the transmission control module

Questions and answers

What does P0748 mean?

It is an electrical fault in the transmission pressure control solenoid circuit. The control module sees an open, short or out-of-range resistance, most often from wiring, a connector or the solenoid itself.

Can I drive with P0748?

Only briefly and carefully, to a repair shop. Limp mode shifts harshly and can quickly wear internal transmission parts.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.