P0747 on 2021-2025 Buick Encore GX: Pressure Control Solenoid 'A' Stuck On Causes and Fixes

What's Unique About the 2021-2025 Buick ENCORE GX

While P0747 typically suggests a faulty solenoid, on the 2021-2025 Buick Encore GX equipped with the 9-speed (9T45) automatic transmission, the root cause is frequently a mechanical failure inside the transmission. General Motors has issued Technical Service Bulletins (TSBs) indicating that out-of-round snap rings or improperly seated clutch retaining rings can trigger this code. TSB PIP5974E explicitly warns technicians *not* to replace the valve body or solenoid assembly for this condition, as the fault lies with the clutch pack's mechanical retaining components. This means simply replacing the solenoid will not fix the problem; the transmission itself requires internal inspection and repair.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Check Engine Light (Malfunction Indicator Lamp) is on.
• Harsh, jerky, or slamming gear shifts, especially from Park into Drive.
• Transmission slipping, where engine RPMs rise without an increase in vehicle speed.
• Delayed engagement when shifting into gear.
• Vehicle may enter "limp mode," getting stuck in a single gear.
• A buzzing or whirring noise from the transmission.
• Complete loss of movement (no-drive condition).

Most Likely Causes

1. Defective or Out-of-Round Transmission Snap Ring 🔴 High Probability → Shop Transmission Assembly As identified in GM TSB #PIP5974E, certain 2024-2025 models may have been built with defective 1-2-3-4-5-6 clutch snap rings that can pop out of their groove, causing this code. This applies to the entire 9TXX transmission family.
   How to confirm: A technician must check the transmission's Julian build date. If it falls between 10/1/2023 (23-274) and 4/22/2024 (24-113), internal inspection is required if the code is present and resets on a test drive.
   Typical fix: The transmission must be disassembled to inspect and replace the faulty snap rings and any damaged clutch components. TSB PIP5974E lists specific parts to replace, including the clutch piston housing, seals, and clutch plates. In many cases, the entire transmission assembly is replaced.
   Est. part cost: $50-$200 for rings, $4000+ for transmission assembly
2. Improperly Seated Clutch Spring Retaining Ring 🔴 High Probability GM Service Update #N202321842 01 notes that on certain 2021 models, the clutch spring retaining ring may not have been fully seated from the factory, leading to code P0747 at very low mileage. This was a service campaign for vehicles in dealer inventory.
   How to confirm: A specific dealer inspection procedure was required. If shift bumps were felt during the test drive, the condition was confirmed. This campaign expired in Feb 2022, but the underlying issue could still be present.
   Typical fix: Per the service update, dealers were instructed to replace the entire transmission assembly if the inspection failed.
   Est. part cost: $4000+ for transmission assembly
3. Faulty Pressure Control Solenoid 'A' ⚪ Low Probability → Shop Transmission Valve Body While this is the textbook definition of the code, on this platform it's often a symptom of the mechanical issues above rather than the root cause. TSBs specifically advise against replacing the solenoid for this condition.
   How to confirm: A technician can use a bi-directional scan tool to command the solenoid on and off to check its response. The solenoid's electrical resistance can also be tested with a multimeter.
   Typical fix: Replacement of the solenoid, which is located inside the transmission on the valve body. This should only be done after ruling out the TSB-related mechanical failures.
   Est. part cost: $50-$150
4. Low or Contaminated Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly
   How to confirm: Check the transmission fluid level and condition. The fluid should be at the correct level, red, and free of debris or a burnt smell. Note: This transmission does not have a user-serviceable dipstick. Metal shavings in the fluid would be a strong indicator of the internal snap ring failure.
   Typical fix: Perform a transmission fluid drain-and-fill or a complete fluid flush. If the fluid is very dirty or contains metal, it indicates internal damage requiring teardown.
   Est. part cost: $150-$400 for fluid and filter service

Rare But Worth Checking

• Wiring Harness Issue: A short or open in the wiring between the TCM and the transmission can mimic a solenoid failure. This should be checked before condemning internal components.
• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly In rare cases, the TCM itself can fail, sending an incorrect signal. This is unlikely and should be the last item to be diagnosed after all other possibilities are ruled out.

Diagnosis Steps

1. Use an OBD-II scanner to confirm P0747 and check for any other related transmission codes like P0700 or P0746.
2. Check for any applicable Technical Service Bulletins (TSBs) for your vehicle's specific VIN. For the Encore GX, TSBs #PIP5974E and Service Update #N202321842 01 are highly relevant.
3. For 2024-2025 models, check the transmission's Julian build date to see if it falls within the range specified in TSB #PIP5974E (Oct 2023 - Apr 2024).
4. Inspect the transmission fluid level and condition (professional service required). Dark, burnt, or metallic-flecked fluid indicates internal wear, likely related to the snap ring failure.
5. If TSBs do not apply, perform an electronic diagnosis. Use a bi-directional scan tool to monitor the commanded state vs. the actual state of Pressure Control Solenoid 'A'.
6. Inspect the wiring harness and connectors between the TCM and the transmission for any signs of damage, corrosion, or looseness.
7. If TSBs do apply, follow the manufacturer's procedure, which likely involves internal transmission inspection and repair or, more commonly, a full transmission replacement.

Parts You'll Likely Need

• Transmission Assembly (OEM #24283290) — Per GM service bulletins for this code, a failed inspection due to an internal retaining ring or snap ring issue requires a full transmission replacement. This part number fits both the Encore GX and Chevrolet Trailblazer with the 9-speed automatic transmission.
  Trusted brands: ACDelco, GM Genuine Parts
  OEM price range: $4000-$5000
  Aftermarket price range: $3000-$4500
• 1-2-3-4-5-6 Clutch Piston Housing and Snap Rings — If a technician opts to repair the existing transmission instead of replacing it per TSB PIP5974E, these are the internal components cited as the root cause of the problem. The TSB lists a bill of materials for this repair.
  Trusted brands: ACDelco
  OEM price range: $200-$500 (for kit of internal parts)
  Aftermarket price range: $150-$350
• Pressure Control Solenoid 'A' — This part is replaced only when diagnosis confirms it is electrically faulty and the known TSBs do not apply to the vehicle. This is an uncommon fix for this specific platform and code.
  Trusted brands: ACDelco
  OEM price range: $80-$150
  Aftermarket price range: $40-$90

Related Codes That Often Appear With This One

• P0746 — This code for 'Pressure Control Solenoid 'A' Performance/Stuck Off' is the counterpart to P0747. TSB PIP5974E explicitly lists both codes as resulting from the same internal 1-2-3-4-5-6 clutch snap ring issue.
• P0700 — This is a generic code indicating that the Transmission Control Module (TCM) has requested the check engine light to be turned on. It is a general fault code that will almost always be present alongside more specific transmission codes like P0747.

Technical Service Bulletins (TSBs) & Recalls

• PIP5974E: Communicates that an out-of-round transmission 1-2-3-4-5-6 clutch snap ring can cause codes P0746 or P0747 on 2024-2025 models. It provides a specific date range for affected transmissions.
• N202321842 01: A service update for certain 2021 models concerning a clutch spring retaining ring that may not be fully seated, which can cause DTC P0747.

Platform-Specific Known Issues

• TSB #PIP5974E documents that some 2024-2025 models may have out-of-round 1-2-3-4-5-6 clutch snap rings, causing codes P0746 or P0747. The bulletin explicitly states not to replace the valve body or solenoids.
• Service Update #N202321842 01 was issued for certain 2021 models where the clutch spring retaining ring may not have been fully seated, leading to P0747 at low mileage and requiring transmission replacement. This was a stop-delivery campaign for unsold vehicles.

Mechanic-Grade Diagnostic Values

• Pressure Control Solenoid 'A' (1-2-3-4-5-6 Clutch) Resistance — expected: 5.0 - 5.4 Ω at 20°C (68°F). Failure: A resistance reading outside of this range indicates a faulty solenoid coil.

Scan Tool Commands That Help

• GDS2 (GM Diagnostic Software): Solenoid Valve Test / Control Functions — This active test allows a technician to command individual solenoids on and off to verify their electrical and mechanical response, isolating a faulty solenoid from a wiring or control module issue.
• GDS2 (GM Diagnostic Software): Transmission Service Fast Learn Procedure — This procedure must be performed after replacing the transmission, valve body, or TCM to allow the module to relearn clutch apply points and ensure smooth shifting.

Wiring & Ground Locations

• Transmission Control Module (TCM/TEHCM) — The TCM is integrated into the Transmission Electro-Hydraulic Control Module (TEHCM), which is bolted to the valve body inside the transmission oil pan.. Accessing the TCM or solenoids requires removing the transmission pan and draining the fluid, making it a labor-intensive job.
• Body Control Module (BCM) — Located in the center console, on the front passenger side of the vehicle.. The BCM provides a key power supply to the TCM for its power-down self-test. A fault in the BCM or its wiring can cause a false P0747 code.
• BCM Connector X4, Pin 22 — On the Body Control Module (BCM).. This specific pin supplies voltage to the TCM. A technician can probe this pin to verify if voltage is present for at least 15 seconds after the ignition is turned off. If not, it points to a BCM or wiring fault, not a transmission fault.

"I Checked Everything" — The Actual Cause

• A known edge case for P0747 on 9T transmissions occurs when the solenoid and wiring test perfectly. The actual cause can be the Body Control Module (BCM) failing to supply voltage to the Transmission Control Module (TCM) for at least 15 seconds after the ignition is switched off. The TCM uses this power-down window to perform a self-test on the solenoids (a 'dither' test). If power is cut prematurely, the test doesn't complete, and the TCM falsely flags P0747 on the next startup, assuming the solenoid is stuck.

OEM Part Supersession History

• 24283290 → 19431565 — Part update or revision by the manufacturer.
  Heads up: One parts vendor suggests 24283290 is replaced by 19431565, but other vendors still list 24283290 as correct for 2021-2024 models. Always confirm the correct part number with a dealer using the vehicle's VIN before ordering.

Model Year Variations Within This Range

• 2024-2025: The 2024 model year introduced a significant refresh with new front-end styling and a completely updated interior featuring a large digital dashboard with an 11-inch touchscreen. While the 9-speed automatic transmission for AWD models remains mechanically the same, the updated Body Control Module (BCM) and interior wiring for the new tech could complicate the diagnosis of electrical edge cases like the BCM power-down fault.