P0796 on GMC: How to Diagnose & Fix
Pressure Control Solenoid 'C' Performance or Stuck Off
1 GMC model · 1 documented issue · 1 critical · $1,800-$4,500 repair
P0796 on GMC by model: symptoms, diagnosis and fix
The 35R clutch wave plate inside the 6T70/6T75 six-speed transaxle cracks and fractures, allowing the 35R clutch piston to overstroke and leak apply pressure. The result is a hard flare or slip in 3rd and 5th gear and eventually a complete loss of reverse. Failures typically begin after about 25,000 miles and are extremely common on the early Lambda Acadia; GM eventually extended coverage on the wave plate to 10 years/120,000 miles. Debris from the broken plate circulates through the transmission, so a simple plate swap is often not enough on high-mileage units.
Common Symptoms
- No reverse gear
- Slip or flare shifting into 3rd gear
- Harsh or delayed 3-5 shifts
- Check engine / SES light on
- RPM flares under acceleration then catches
How to Fix
Transmission must come apart. The correct repair is replacement of the 35R clutch wave plate with the redesigned/updated part plus new 35R clutch pack and seals, a thorough flush of the cooler and valve body, and a fluid/filter change. On units run for a long time after failure, a full rebuild or remanufactured transaxle is the realistic fix. Check eligibility under the extended special coverage before paying out of pocket.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Sonnax 3-5-Reverse Drum Saver Kit (upgraded wave plate + cupped steel)Cross-refSonnax 124555K$55–$120
Fits Gen.1 and Gen.2 6T70/6T75 — the 2007-2012 Ac
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
P0796 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0796 mean on a GMC?
P0796 stands for "Pressure Control Solenoid 'C' Performance or Stuck Off." This generic transmission code means the TCM/PCM detected that pressure control solenoid 'C' is not regulating hydraulic pressure as expected, or appears stuck in the off position. These solenoids control the line pressure that applies the transmission's clutch packs to achieve the correct gear ratios, so a performance fault here disrupts shift quality. Symptoms can include harsh or delayed shifts, slipping, or limp mode, and continued driving can accelerate transmission wear. On GMC it is documented across 1 model: Acadia.
What are the most common causes of P0796?
The most common causes of P0796 are: Faulty pressure control solenoid C, Low, dirty, or degraded transmission fluid, Blocked or restricted valve body fluid passages, Damaged wiring or connector to the solenoid, Worn valve body or stuck valve, Internal transmission mechanical wear, Faulty TCM/PCM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0796 on a GMC?
Published repair estimates on GMC range from $1,800 to $4,500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0796 on a different make?
View P0796 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.