P0746
PowertrainPressure Control Solenoid 'A' Performance or Stuck Off
The gearbox runs on hydraulic pressure, and pressure control solenoid 'A' is one of the electrical valves that meters that pressure on demand. When the transmission control module commands a pressure change and the actual reading doesn't follow, or the solenoid looks stuck shut, it logs P0746. For you as the driver, it means the box can no longer reliably control its own shift pressure, so changes go soft, harsh, or stop happening altogether.
ⓘ Information only. This page provides general educational information about fault code P0746. We do not assess the urgency or safety implications of any specific fault. That requires in-person diagnosis by a qualified mechanic. Full terms.
Recommended next steps
Whether a fault is urgent, drivable, or routine depends entirely on the cause on a specific vehicle, and that can only be determined by a qualified mechanic with diagnostic equipment. If a warning light is illuminated, the most reliable next step is professional diagnosis.
What does P0746 mean?
P0746 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Pressure Control Solenoid 'A' Performance or Stuck Off.
This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.
Symptoms commonly associated with this code
Symptoms that drivers often report alongside this code. Not all may apply to every case:
- • Gearbox or engine warning light on, sometimes with a separate transmission fault lamp depending on the make
- • Harsh, banging gear changes, particularly the 1-2 shift when pulling away
- • Slipping, where the revs climb but the car doesn't pick up speed to match
- • Long pause or hesitation before the box drops into gear from a standstill
- • Car dropping into limp mode and holding a single gear, usually third, until you restart it
- • Worse fuel economy because the transmission is shifting at the wrong points
Possible causes
Causes commonly associated with P0746, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. The pressure control solenoid 'A' has failed internally or jammed shut, the most common reason this code appears on its own
- 2. Low or burnt transmission fluid, which is a frequent culprit on boxes that have never had a fluid change. Old fluid loses its properties and clogs the solenoid
- 3. Blocked or collapsing transmission filter starving the valve body of clean fluid flow
- 4. Damaged or corroded wiring and connectors at the solenoid or the main transmission plug, often from heat and road salt underneath
- 5. Worn valve body, where the bore the solenoid sits in has worn oval and lets pressure bleed off
- 6. Faulty transmission fluid pressure sensor feeding the TCM duff readings so it thinks the solenoid is misbehaving
- 7. TCM software glitch or internal driver fault, rarer but does happen on higher-mileage units
How mechanics typically diagnose
A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training.
- 1. Pull the codes and freeze-frame data first, then check whether the fault is current or historic and what gear and temperature it logged at
- 2. Check the transmission fluid level and condition while you're under there. Dark fluid that smells burnt tells its own story, and a lot of these go away after a proper fluid and filter service
- 3. Inspect the solenoid connector and harness for green corrosion, chafed insulation, or a loose pin before you condemn anything expensive
- 4. Measure the solenoid resistance against the workshop figure for that box, and check it's switching when commanded
- 5. Take it for a drive with a scan tool reading live line pressure and commanded versus actual solenoid duty, this is where a sticking solenoid shows itself clearly
- 6. If the electrics and fluid all check out, drop the sump and look at the valve body for wear and debris
Common questions about P0746
What happens if I just keep driving it like this? +
You risk turning a solenoid job into a full gearbox rebuild. When the box can't control its own pressure, the clutch packs slip and overheat, the fluid cooks, and the metal debris that comes off circulates through the whole unit. A solenoid and fluid service might be a few hundred pounds. A slipped, burnt gearbox is a four-figure job. Keep journeys short and gentle until it's looked at.
How quickly do I need to sort this out? +
Soon. It's not a roadside emergency the moment the light comes on, but it's not something to leave for months either. If it's already going into limp mode or banging through gears, treat it as a priority and book it in within days rather than weeks. The longer it slips, the more damage stacks up.
Is it the solenoid itself or could it just be the wiring? +
Both are real possibilities and that's exactly why you test before you buy parts. Check the connector and harness for corrosion and chafing first, because a duff plug or a broken wire mimics a failed solenoid perfectly. Plenty of these turn out to be a dirty fluid problem too. Only condemn the solenoid once the wiring is clean, the resistance is in spec, and the fluid is good.
How long is the car off the road for the repair? +
A fluid and filter service is a couple of hours. A solenoid replacement where it's accessible through the sump is usually most of a day with the fluid refill and a road test. If the valve body has to come off or the box needs to drop, you're looking at a day or two, longer if the garage is waiting on parts for an older or less common model.
Information only, not professional advice
The information on this page is provided for general guidance and educational purposes only. It is not a substitute for diagnosis or repair advice from a qualified mechanic. Always verify any fault before paying for repairs. carfaultcodes.co.uk accepts no liability for decisions made based on this information. Full terms →