P0796
PowertrainPressure Control Solenoid C Performance Or Stuck Off
You'll usually feel this one before you see the light. The car bangs into gear, holds a ratio too long, or slips and flares the revs when it should be changing cleanly. Behind all that is pressure control solenoid C, which is one of the valves that meters hydraulic pressure inside the gearbox to engage clutches and bands. The TCM has worked out that solenoid C either isn't responding or has stuck in the off position, so the pressure it's asking for isn't showing up, and it throws P0796 and often drops the box into limp mode to protect itself.
ⓘ Information only. This page provides general educational information about fault code P0796. 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 P0796 mean?
P0796 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Pressure Control Solenoid C 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:
- • Harsh, clunky gear changes, worst when you're accelerating away from a junction
- • Revs flaring or the box slipping between ratios instead of grabbing cleanly
- • Engine warning light on, sometimes with a transmission or gearbox warning too
- • Car stuck in limp mode, usually locked in third gear with no other selection
- • Stalling as you slow to a stop, especially on cars where the converter lock-up is involved
- • Sluggish response and a noticeable drop in economy while it's faulting
Possible causes
Causes commonly associated with P0796, listed in approximate order of typical investigation. The actual cause on a specific vehicle can only be confirmed by professional diagnosis.
- 1. Old, low, or burnt transmission fluid gumming up the solenoid so it can't move freely. This is the first thing to rule out and the cheapest to fix
- 2. Pressure control solenoid C itself stuck mechanically or failed electrically, common once the fluid has been left too long
- 3. Wiring or connector trouble at the solenoid, corroded pins or a poor earth giving the TCM the wrong picture
- 4. Debris and clutch material clogging the valve body passages, which stops the solenoid regulating pressure properly
- 5. Worn internal clutches, seals, or bands that can't hold pressure no matter what the solenoid does
- 6. Faulty TCM commanding the solenoid incorrectly, the least likely of the lot but it does happen
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 write down everything stored, not just P0796. Other transmission codes alongside it point you straight at whether it's electrical, hydraulic, or mechanical
- 2. Check the fluid level and condition next. Pull the dipstick or do it through the fill plug, and if the fluid is dark, smells burnt, or has glitter in it, you've likely found a big part of the answer
- 3. Inspect the wiring and connector at solenoid C for chafing, corrosion, and loose pins. Wiggle-test it with live data running if you can
- 4. Measure solenoid resistance with a multimeter, expect roughly 4 to 7 ohms. Open or shorted readings condemn the solenoid
- 5. Watch live data for what the TCM is commanding versus the actual line pressure. A command with no pressure response tells you the solenoid or valve body isn't acting on it
- 6. Clear the code and road-test through the full range of gears under load to see whether it comes straight back
Common questions about P0796
Can I keep driving it like this or do I need to stop? +
Don't keep using it for normal running. Limp mode and slipping clutches mean the box isn't getting the pressure it needs, and every mile of slip and overheating chews up the clutch packs faster. A short, gentle drive home or to a garage is fine. Daily commuting on it is how a £200 solenoid job turns into a rebuild. If it's banging into gear or flaring badly, park it and get it looked at.
Is it the solenoid that's gone, or could it just be wiring or dirty fluid? +
All three are in play and you check them in that order. Plenty of P0796 faults clear up after a proper fluid and filter service because thickened, contaminated oil stops the solenoid sliding. After that, a damaged connector or chafed wire can mimic a dead solenoid, so an ohm test and a wiggle test sort the electrical side. Only once fluid and wiring are confirmed good should you condemn the solenoid itself.
How long does the job take once it's diagnosed? +
Diagnosis is usually an hour or so on a scan tool with the car up. A fluid and filter service to clear a sticky solenoid is a half-day job at a garage. Replacing the solenoid means dropping the pan and getting at the valve body, figure three to five hours of labour on most autos. If they end up pulling and stripping the valve body or going deeper into the box, you're looking at the best part of a day or more.
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 →