P0745 and related codes: pressure control solenoids A to F

What does P0745 mean?

Pressure control solenoids, sometimes called line pressure or variable force solenoids, decide how hard the clutches inside the gearbox are pressed together. The gearbox computer varies the current through them to make each change firm or smooth and to stop the clutches slipping. If one sticks or its circuit fails, the computer usually raises pressure to the maximum or holds one gear, so changes become harsh or the car stays in limp mode.

What causes P0745?

1. Worn or dirty transmission fluid, which wears and jams these precise valves
2. A failed pressure solenoid coil or an internal short
3. A damaged wire or a connector on the gearbox that lets fluid in
4. A worn valve body in which the solenoid's valve sticks
5. A gearbox computer that no longer drives the solenoid

What to check first for P0745

• Check the fluid level and condition, and when it was last changed
• Read all transmission codes: a circuit code points to wiring, a performance code more to the solenoid or the fluid
• Measure the pressure solenoid's resistance at the gearbox connector
• Have the solenoid commanded with a scan tool while line pressure is watched, before the gearbox is opened

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