P0750
PowertrainShift Solenoid 'A' Malfunction
Most of the time this is a worn or sticking shift solenoid inside the gearbox, often after the fluid has been left too long and gone gritty. Shift solenoid 'A' controls the hydraulic fluid that lets the box change between first and second. When the transmission control module commands a shift and doesn't see the gear actually change, or the solenoid circuit reads wrong electrically, it logs P0750 and usually drops the box into limp mode to protect itself.
ⓘ Information only. This page provides general educational information about fault code P0750. 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 P0750 mean?
P0750 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Shift Solenoid 'A' Malfunction.
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:
- • Engine warning light, sometimes alongside a separate gearbox or overdrive warning lamp
- • Harsh, delayed or clunky changes between 1st and 2nd, you'll feel it pull away rough
- • Box stuck in one gear, commonly 3rd, which is limp mode trying to get you home safely
- • Slipping under acceleration, revs climb but the car doesn't pull as it should
- • Worse fuel economy because the box is sat in the wrong gear
- • Car feels gutless or laboured, especially pulling away from junctions
Possible causes
Causes commonly associated with P0750, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Worn or sticking shift solenoid 'A', the usual culprit, the internal valve gums up or the coil starts failing
- 2. Old, low or contaminated transmission fluid, particularly boxes that have never had a fluid service. Fluid full of fine metallic glitter is a bad sign
- 3. Clogged transmission filter starving the valve body of clean fluid
- 4. Damaged or corroded wiring and connector at the solenoid, water and road salt get into the loom on older cars
- 5. Faulty TCM or PCM, less common but it does happen on high-mileage cars
- 6. Worn valve body or internal mechanical wear, the expensive one nobody wants to find
- 7. Fluid leak dropping the line pressure so the box can't build enough to shift cleanly
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 all stored codes and the freeze frame data first. P0750 rarely turns up alone, and what sits next to it tells you whether you're chasing a solenoid or a dying gearbox
- 2. Check the fluid level and condition properly. Sniff it for a burnt smell, look at the colour on a clean rag, and check for metal glitter. Dark, smelly fluid points at internal wear, not just a lazy solenoid
- 3. Inspect the solenoid connector and wiring for corrosion, green crud on the pins or a damaged loom. A duff connection mimics a failed solenoid perfectly
- 4. Back-probe the solenoid circuit and run voltage and ground continuity checks. Compare resistance against the manual figures, a coil that's gone open or shorted shows up here
- 5. Bench or in-situ test the solenoid by feeding it 12V and listening for a clean click. No click usually means a dead solenoid
- 6. Road test on a scan tool at 15 to 35 mph, watching commanded gear against actual gear. If the TCM asks for 2nd and nothing happens, you've confirmed the fault is real and not just an electrical glitch
Common questions about P0750
Should I just buy a cheap solenoid off the internet or pay for a proper one? +
Stick with an OEM or a known transmission brand for this. Shift solenoids work to tight tolerances and the cheap pattern parts off eBay are a common reason a fault comes straight back after the job. You'll have already paid for the labour to drop the pan, so spending an extra £40 to £80 on a quality solenoid rather than a no-name special is false economy if it fails again. On a lot of boxes the solenoids come as a pack anyway, so buy the proper pack once and forget about it.
Can I keep driving it like this for a bit? +
I wouldn't. If it's dropped into limp mode and stuck in one gear, that's the box protecting itself, and pulling away in 3rd or labouring on the motorway just cooks the fluid and the clutch packs. A few short careful trips to the garage are one thing. Daily commuting on a slipping box is how a £300 solenoid job turns into a £1,500 rebuild. Get it looked at sooner rather than later.
Is this going to fail my MOT? +
The solenoid fault itself isn't an MOT test item, the tester doesn't check gearbox operation. The catch is the warning light. If the MIL is lit when the car goes in, that's an automatic fail under the current rules. Fix the fault, clear the light and let it run a few drive cycles to confirm it stays off before you book the test.
What sort of money am I looking at to sort it? +
Depends entirely what's actually wrong. A fluid and filter service or a wiring repair might be a couple of hundred quid. A solenoid replaced at an independent gearbox specialist typically lands in the mid hundreds once labour for dropping the pan is in, while a main dealer will charge a fair bit more. If it turns out the valve body or the box internals are worn, you're into four figures, and at that point a recon or used gearbox starts to make more sense. An auto transmission specialist will nearly always be cheaper and more honest about it than a franchised dealer.
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 →