P0746 on 2018-2025 Chevrolet Traverse: Causes and Fixes for Transmission Issues

What's Unique About the 2018-2025 Chevrolet TRAVERSE

The 2018-2025 Traverse uses a GM 9-speed automatic transmission (RPO code M3V, part of the 9TXX series, specifically the 9T65 for the V6). While the code points to a solenoid, these transmissions have a documented, widespread history of internal mechanical failures triggering it. Manufacturer Technical Service Bulletin (TSB) #PIP5974E specifically links P0746 to out-of-round snap rings for the 1-2-3-4-5-6 clutch in transmissions built between October 1, 2023, and April 22, 2024. This indicates a specific manufacturing flaw, making diagnosis more complex 🎬 Watch a case study on diagnosing this Traverse transmission issue. and repairs more invasive than on other vehicles where a solenoid swap might suffice.

Diagnostic Flowchart

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

Symptoms You May Notice

• Vehicle will not move when in Drive or Reverse.
🎬 See why a 9T65 transmission might lose all forward and reverse gears.
• Sudden loss of propulsion while driving.
• Harsh or delayed shifting, sometimes with a noticeable 'thunk'.
• Transmission gets stuck in one gear (limp mode).
• Check Engine Light or Transmission Warning Light is on.
• Slipping or engine revving without acceleration.
• Transmission overheating message on the driver information center (DIC).

Most Likely Causes

1. Out-of-Round or Broken 1-2-3-4-5-6 Clutch Snap Ring 🔴 High Probability This is a documented manufacturing defect in GM TSB #PIP5974E for the 9TXX transmission family. It specifically affects transmissions with a Julian build date between 23 274 and 24 113 (Oct 1, 2023 - Apr 22, 2024). The bulletin identifies the '(594) 1-2-3-4-5-6 Clutch Spring Retaining Ring' or '(599) 1-2-3-4-5-6 Clutch Backing Plate Retaining Ring' as the culprits.
   How to confirm: The primary confirmation is checking the transmission's build date. If it falls within the affected range, this is the most likely cause. Visual confirmation requires transmission removal and internal inspection. 🎬 Watch this 9T65 rebuild video to see the internal components.
   Typical fix: The transmission must be removed and disassembled to replace the entire 1-2-3-4-5-6 clutch piston housing assembly and related seals and plates. The TSB explicitly warns *not* to replace the valve body or solenoids for this specific issue.
   Est. part cost: $150-$300 for the clutch pack rebuild kit and seals.
2. Fatigued Solenoid Retaining Clips 🔴 High Probability A known weakness in GM's 8, 9, and 10-speed transmissions involves the metal clips that hold the linear solenoids in the valve body. These clips can fatigue and collapse, allowing the solenoid to wobble in its bore, which creates an internal pressure leak and triggers performance codes like P0746.
   How to confirm: This requires removing the transmission valve body cover to inspect the solenoid clips. A collapsed or weak clip is a clear indicator of the problem. Aftermarket company Sonnax makes a reinforcement clip (part #184740-04K) to correct this known issue.
   Typical fix: Replacement of the faulty solenoid retaining clips. This is often done as a set. While less invasive than a full rebuild, it still requires accessing the valve body. Upgraded stabilization clips are available from the aftermarket.
   Est. part cost: $20-$50 for a clip kit.
3. Failed Pressure Control Solenoid 'A' 🟡 Medium Probability → Shop Transmission Valve Body While less common than the mechanical issues on this platform, the solenoid itself can fail electronically or mechanically. However, it is often a symptom of a larger problem rather than the root cause.
   How to confirm: A technician can use a high-end scan tool to command the solenoid and monitor its response and electrical values (amperage draw). Direct testing with a multimeter may also be performed after accessing the solenoid. A variable force solenoid should have a resistance of approximately 5.1 Ohms at 68°F (20°C).
   Typical fix: Replacement of the faulty solenoid. On the 9T65 transmission, solenoids are located on the valve body. If this is the confirmed cause, the specific solenoid (e.g., part #24278294) is replaced.
   Est. part cost: $200-$600 for a solenoid or solenoid body.
4. Low or Contaminated Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly While unlikely to be the root cause given the known TSBs, low or degraded fluid can cause a variety of pressure-related issues that may trigger this code.
   How to confirm: Check the transmission fluid level and condition according to the manufacturer's procedure. The 9T65 transmission does not have a traditional dipstick and must be checked via a level-check plug on the side of the case when the vehicle is at a specific temperature.
   Typical fix: Perform a transmission fluid drain-and-fill using the correct ACDelco DEXRON-VI ULV fluid. If the fluid is low, the source of the leak must be identified and repaired.
   Est. part cost: $150-$300 for fluid and filter.

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly A module failure is rare, but possible. It should only be considered after all mechanical and hydraulic causes have been ruled out.
• Internal Wiring Harness Damage: The wiring inside the transmission leading to the solenoid can become damaged, causing an electrical fault that mimics a failed solenoid.

Diagnosis Steps

1. Verify the code with a professional OBD-II scan tool.
2. Check for any other related transmission codes, especially P0747.
3. Check the transmission's Julian build date. If it falls between 23 274 and 24 113 (Oct 1, 2023 - Apr 22, 2024), suspect the snap ring failure per TSB PIP5974E.
4. Review all available Technical Service Bulletins (TSBs) for the vehicle's VIN. Specifically look for PIP5974E, PIE0720A, and PIE0720.
5. Check the transmission fluid level and condition via the side plug procedure.
6. Use a scan tool to monitor live data, specifically the commanded state vs. the actual state of Pressure Control Solenoid 'A'.
7. If possible, command the solenoid on and off with the scan tool to check for response.
8. If the build date does not point to the snap ring issue, the next step is often dropping the valve body cover to inspect for fatigued solenoid retaining clips.
9. If debris is found in the pan or other steps are inconclusive, the transmission must be removed for internal inspection of the clutch packs and snap rings as described in TSB #PIP5974E.

Parts You'll Likely Need

• Transmission 1-2-3-4-5-6 Clutch Piston Housing and Ring Kit — This is the specific component set identified in TSB #PIP5974E as the fix for the primary cause of P0746 on affected models. The repair requires replacing the housing, piston, seals, and rings as a group.
  Trusted brands: ACDelco (GM Genuine)
  OEM price range: $150-$300
  Aftermarket price range: $100-$200
• Transmission Control Valve Body / Solenoid Body (OEM #24293253) — If the solenoid itself or fatigued clips are confirmed to be faulty, this assembly is often replaced. TSBs warn against replacing this if the snap ring issue is the cause.
  Trusted brands: ACDelco
  OEM price range: $800-$1200
  Aftermarket price range: $500-$900
• Pressure Control Solenoid (OEM #24278294) — If an individual solenoid is diagnosed as faulty and not related to a larger mechanical issue. This part number is for a pressure solenoid in the 9TXX family.
  Trusted brands: ACDelco, Bosch
  OEM price range: $70-$150
  Aftermarket price range: $50-$100
• Automatic Transmission Fluid (ULV) — Required for any transmission service or repair. The 9T65 requires a specific Ultra-Low Viscosity fluid.
  Trusted brands: ACDelco DEXRON ULV
  OEM price range: $20-$30 per quart
  Aftermarket price range: $15-25 per quart

Related Codes That Often Appear With This One

• P0747 — This code means "Pressure Control Solenoid 'A' Stuck On". It is the direct counterpart to P0746. Multiple TSBs, including PIP5974E and PIE0720, cite both codes together as they point to the same underlying mechanical failures in the 1-2-3-4-5-6 clutch hydraulic circuit.
• P0700 — This is a generic code indicating the TCM has requested the Check Engine Light. It acts as a general flag that a more specific transmission code, like P0746, is stored.

Technical Service Bulletins (TSBs) & Recalls

• PIP5974E: Communicates that out-of-round 1-2-3-4-5-6 snap rings can cause P0746 or P0747 in transmissions built between Oct 2023 and Apr 2024, and explicitly warns against replacing the valve body for this fault.
• PIE0720A: Ends a data-gathering period for technicians regarding a no-move condition associated with P0746 and P0747, indicating the issue was under active investigation.
• PIE0720: Instructs technicians to perform checks and contact an engineer for a no-move condition with P0746 and P0747 set, highlighting the known severity.
• PIP5697E: While focused on P0747, this TSB is relevant as it describes a potential BCM or wiring fault that can falsely set a pressure control solenoid code during engine start/stop, which should be ruled out to avoid unnecessary transmission repair.

Platform-Specific Known Issues

• A known issue documented in TSB #PIP5974E points to "1-2-3-4-5-6 snap rings out of round causing code p0746 or p0747". This affects transmissions built between Julian dates 23 274 and 24 113 (Oct 2023 - Apr 2024) and requires a transmission rebuild.
• TSBs #PIE0720A and #PIE0720 were issued by GM Engineering to investigate a "Vehicle Will Not Move" condition directly linked to DTCs P0746 and P0747, confirming the severity of the underlying problem.
• An owner of a 2024 Traverse reported the code appeared while driving at 50mph, creating a safety hazard and requiring the vehicle to be towed for a warranty transmission repair. [NHTSA ODI #11618149]
• Owners on forums like traverseforum.com and Reddit frequently report symptoms of shuddering and a complete loss of reverse gear on 2018+ models, which are consistent with the internal failures that trigger P0746.

Mechanic-Grade Diagnostic Values

• Pressure Control Solenoid (Variable Force) Coil Resistance — expected: 5.1 Ohms +/- 0.3 Ohms at 68°F (20°C). Failure: A reading of 0 Ohms (short) or infinite Ohms (open circuit), or a value significantly outside the expected range. Resistance will increase with temperature, to around 6.7 Ohms at 212°F (100°C).
• On/Off Solenoid Coil Resistance — expected: 12.0 Ohms +/- 0.3 Ohms at 68°F (20°C). Failure: A reading significantly outside this range. Resistance increases to approximately 15.8 Ohms at 212°F (100°C). While P0746 points to a variable force solenoid, checking others is wise if the valve body is accessed.
• Transmission Line Pressure at Idle (in Drive) — expected: Minimum of 55-60 psi. Failure: Pressure below 50 psi indicates a potential issue with the pump, fluid level, or a major internal leak.

Scan Tool Commands That Help

• GDS2 (GM Dealer Tool) or equivalent high-end scanner: Transmission Fast Learn / Service Fast Learn — This procedure is mandatory after any major transmission repair, such as replacing the valve body, solenoids, or internal clutch components. It allows the TCM to learn the hydraulic characteristics and apply pressures of the new parts to ensure proper shift quality.
• GDS2 (GM Dealer Tool) or equivalent high-end scanner: Solenoid Valve Control — Used during diagnosis to command a specific solenoid on or off to verify its mechanical and electrical response. This helps isolate a faulty solenoid from a wiring or TCM issue.
• GDS2 (GM Dealer Tool) or equivalent high-end scanner: Reset Transmission Adaptations — Used after a fluid change or minor repair to clear the learned shift data. The transmission will then relearn the driver's habits. This is less comprehensive than a Fast Learn but useful for addressing shift quality complaints.

Real Owner Repair Stories

• NHTSA ODI #11618149 (2024 Chevrolet Traverse) — Vehicle was moving at approximately 50mph when it lost propulsion, presenting a safety hazard. An Onstar diagnostic scan revealed a P0746 code.
  ✅ What actually fixed it The vehicle was towed to a dealer, who indicated the transmission would be repaired under warranty. While the specific part is not named, the symptoms and code align perfectly with the known snap ring failure described in TSB #PIP5974E.

OEM Part Supersession History

• N/A → 184740-04K (Sonnax) — The original GM solenoid retaining clips are prone to fatiguing and collapsing, allowing the solenoid to wobble and cause pressure loss. Sonnax developed part #184740-04K, a 'Solenoid Stabilization Clip Insert', which is used with the original clip to reinforce it and prevent collapse.

Model Year Variations Within This Range

• 2023-2024: Transmissions with a Julian build date between 23 274 (October 1, 2023) and 24 113 (April 22, 2024) are highly susceptible to an internal snap ring failure due to a manufacturing defect, as documented in TSB #PIP5974E. This is the most likely cause for P0746 in this specific date range.