A pressure control solenoid inside the gearbox is stuck or lazy. Line pressure is wrong, so the box slips or bangs into gear.
P0746 — also written PO746, P 0746, 0746 — is the OBD-II code for pressure control solenoid 'a' performance / stuck off. Same code, same fix: this page covers every spelling of it.
P0746 is a transmission fault code, typically costing £250–£2200 to put right in a UK garage.
What causes P0746?
- Contaminated or degraded transmission fluid
- Stuck solenoid in the valve body
- Worn valve body bores
- Debris from a failing clutch pack
How P0746 is fixed
- Fluid and filter service with the correct specification fluid
- Replace or recondition the valve body / mechatronic unit
- Inspect the sump magnet for clutch material
P0746 repair cost in the UK
Most P0746 repairs land between £250–£2200 including parts and labour. The spread is wide because the cheap fix (a sensor, a hose, a leak) and the expensive fix (a major component) throw the same code — which is why a proper diagnosis before parts are bought saves the most money.
Can you drive with P0746?
No. A slipping automatic overheats and turns a solenoid job into a gearbox rebuild.
Urgency: high.
What P0746 is telling you
Gearbox faults are logged when the shift the control unit asked for is not the shift it measured. Fluid condition and level affect that measurement as much as any electrical part, which is why the fluid is checked before anything is dismantled.
On P0746 specifically — pressure control solenoid 'a' performance / stuck off — the stored code records the moment that check failed, not the moment the part gave up. That gap is why two cars with the same code can need completely different repairs.
How P0746 is diagnosed properly
Each of the known causes is ruled in or out in cost order, cheapest and most likely first. On P0746 that means working through them like this:
- Contaminated or degraded transmission fluid — checked for level and condition first, as the cheapest possible cause and a common one.
- Stuck solenoid in the valve body — commanded on and off with the diagnostic tool while its current draw and movement are watched, which separates a stuck part from a dead circuit.
- Worn valve body bores — commanded on and off with the diagnostic tool while its current draw and movement are watched, which separates a stuck part from a dead circuit.
- Debris from a failing clutch pack — confirmed with live data before any part is bought.
An hour of diagnostic time on P0746 routinely saves more than it costs, because the alternative is buying the most expensive part on that list and hoping.
The repairs that actually clear P0746
- Fluid and filter service with the correct specification fluid
- Replace or recondition the valve body / mechatronic unit
- Inspect the sump magnet for clutch material
After the repair the code is cleared and the car is driven until the relevant readiness monitor completes, rather than handed back as soon as the light goes out. A code that has only been erased will come straight back on the next drive cycle.
What happens if P0746 is ignored
This is a stop-and-sort fault rather than a wait-for-the-service fault. Ignoring it risks turning a sensor-money repair into a component-money one.
For reference, P0746 typically lands at £250–£2200 all-in at an independent garage in the UK — main-dealer quotes for the same job usually sit above that.
Getting P0746 looked at
Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0746 is showing on your car, bring the scan results with you — we will read the live data ourselves, tell you which of the causes above it actually is, and price the repair before any work starts.