Transmission

P0745 — Transmission Pressure Control Solenoid Malfunction

Severity: medium Drive with care, to a shop

What P0745 means

The pressure control solenoid sets line pressure, which determines how firmly hydraulic fluid applies the clutches in an automatic transmission. The engine or transmission control module commands it and compares the expected current or pressure with what actually happens. If the circuit is open, shorted or the pressure doesn't match the command, P0745 is stored. It affects the quality of every shift.

Symptoms

  • Harsh shifts in all gears
  • Slipping under acceleration, with revs rising but little speed gain
  • Transmission stuck in limp mode (fixed gear)
  • Check Engine or transmission warning light on
  • Delayed or banging engagement into Drive or Reverse
  • Poor acceleration and higher fuel use

Possible causes

  1. Failed pressure control solenoid
  2. Dirty, old or burnt transmission fluid
  3. Valve body wear or contamination (stuck valves, clogged passages)
  4. Damaged wiring or connector at the solenoid, corroded pins
  5. Low fluid level or clogged filter
  6. Faulty transmission control module (TCM) or engine computer
  7. Faulty line pressure (TFP) solenoid or related sensors

How to diagnose

  1. Scan all modules for codes and freeze frame data, noting any other transmission or engine codes
  2. Check transmission fluid level and condition: color, smell and metal debris
  3. Inspect the transmission wiring harness and connector for damage, moisture and corrosion
  4. Measure solenoid resistance with a multimeter and compare to the spec for your vehicle
  5. Check power and ground at the solenoid connector and test wiring continuity to the control module
  6. Use a scan tool to command the solenoid and watch actual pressure in live data
  7. Drop the pan and inspect the filter and magnet for debris; evaluate the valve body if needed
  8. Measure line pressure with a gauge if access is available

Common fixes

  • Change the transmission fluid and filter per schedule
  • Replace the pressure control solenoid
  • Repair the wiring or connector
  • Clean or rebuild the valve body and replace worn parts
  • Reflash or replace the transmission control module once confirmed faulty

Questions and answers

What does code P0745 mean?

It signals a problem in the circuit or operation of the solenoid that controls automatic transmission line pressure. It can cause harsh shifts, slipping and limp mode.

Can I drive with P0745?

Only briefly and gently, enough to reach a shop. Incorrect pressure causes slipping that wears clutches quickly and can lead to an expensive repair.

Will a fluid change fix P0745?

Sometimes, if dirty fluid or a clogged filter is the cause. If the solenoid or wiring is faulty, you'll need a replacement part or a circuit repair.

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.