P0747 on GMC
Pressure Control Solenoid Stuck On
P0747 on GMC vehicles indicates pressure control solenoid stuck on. Au7o has documented this code across 2 GMC models — most commonly on Sierra 1500, Sierra 3500HD. This transmission code means the pressure control solenoid 'A' is stuck in the on (or fully applied) position, or its circuit behaves as if permanently energized. This solenoid regulates hydraulic line pressure that controls clutches and shift feel inside the automatic transmission. When it stays on, line pressure can't be modulated properly, leading to harsh shifts, slipping, overheating, or the transmission being stuck in a gear or limp mode. It points to the solenoid, its wiring, or a hydraulic/contamination problem in the valve body. Typical repair costs on GMC range from $500 to $6,500, depending on the specific model and root cause.
Common Causes of P0747
- •Stuck or failed pressure control solenoid
- •Dirty or contaminated transmission fluid blocking the valve
- •Debris stuck in the valve body bore
- •Shorted or chafed solenoid wiring
- •Corroded or loose solenoid connector
- •Low or degraded transmission fluid
- •Faulty transmission control module (less common)
P0747 on GMC by Model
GMC Sierra 1500(1 issue)
- 10L80/10L90 10-Speed Valve Body Failure — Loss of Reverse, Limp Mode, and Year-Long Parts Backorder2024-2025
2024-2025 Sierra 1500 trucks with the 10-speed automatic (5.3L L84, 6.2L L87 and 3.0L Duramax LZ0) are failing at very low mileage with a stuck valve-body solenoid. Symptoms: a 'Service Transmission' or 'Service Transmission — Unable to Shift Soon' message, sudden hard/slamming shifts, slipping, complete loss of reverse (owners have had to push the truck out of parking spaces), and default limp operation limited to fifth gear and reverse. Several complaints report the failure occurring under 7,000 miles. NHTSA reports cite DTC P2818 (pressure control solenoid) and P0747/P0700. The situation is compounded by a national valve-body backorder — owners document 50-plus days and in some cases over a year waiting for the part, with GM sometimes authorizing a full transmission replacement instead. Complaint ODI numbers include 11756150, 11754176, 11748050, 11744152, 11739083, 11727368, 11721983, 11694617, 11684139, 11680422, 11680435, 11654431, 11644523, 11634982 (2024) and 11711937 (2025).
GMC Sierra 3500HD(1 issue)
- Allison 1000 Transmission Control Module and Sensor Failures2008-2019
The Allison 1000 transmission paired with the Duramax diesel in 2008-2015 Sierra 3500HD trucks has a high failure rate for the Transmission Control Module (TCM). A class action suit was filed covering these years. Additional issues include input/output speed sensor failures causing no-forward/reverse conditions, and certain 2012 trucks built with incorrect thrust bearings.
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View P0747 across all makes →Frequently Asked Questions
What does P0747 mean on GMC?▼
P0747 stands for "Pressure Control Solenoid Stuck On." This transmission code means the pressure control solenoid 'A' is stuck in the on (or fully applied) position, or its circuit behaves as if permanently energized. This solenoid regulates hydraulic line pressure that controls clutches and shift feel inside the automatic transmission. When it stays on, line pressure can't be modulated properly, leading to harsh shifts, slipping, overheating, or the transmission being stuck in a gear or limp mode. It points to the solenoid, its wiring, or a hydraulic/contamination problem in the valve body. On GMC specifically, this code is documented across 2 models.
What causes P0747 on GMC vehicles?▼
Common causes on GMC: Stuck or failed pressure control solenoid, Dirty or contaminated transmission fluid blocking the valve, Debris stuck in the valve body bore, Shorted or chafed solenoid wiring, Corroded or loose solenoid connector. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0747 on a GMC?▼
Repair costs on GMC range from $500 to $6,500, depending on the specific model and root cause.
Which GMC models have P0747 documented?▼
Au7o has documented P0747 on 2 GMC models: Sierra 1500, Sierra 3500HD.