P0746 on 2019-2024 Chevrolet Blazer: Causes for Pressure Control Solenoid 'A' Faults

What's Unique About the 2019-2024 Chevrolet BLAZER

For the 2019-2024 Chevrolet Blazer, which uses a 9-speed (9TXX) automatic transmission, P0746 is more than just a generic solenoid code. General Motors has issued multiple Technical Service Bulletins (TSBs) indicating this code is often a symptom of a significant internal mechanical failure. Specifically, TSB #PIP5974E points to out-of-round snap rings for the 1-2-3-4-5-6 clutch, which requires a complete transmission teardown to fix. 🎬 See what a full 9T65 transmission rebuild looks like The TSB explicitly warns technicians *not* to replace the valve body or solenoid assembly for this concern, as the root cause is mechanical. This elevates the issue from a potential solenoid swap to a major, and costly, internal repair.

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 in Drive or Reverse
🎬 Watch: Real-world example of a Blazer that won't move
• Sudden loss of propulsion while driving
• Harsh or abrupt shifting
🎬 Watch: Diagnosing a 9-speed transmission that slips and bangs
• Transmission slipping (engine revs but vehicle doesn't accelerate)
• Transmission gets stuck in one gear
• Check Engine Light is on
• Vehicle enters 'limp mode'
• Transmission overheating message on the driver information center

Most Likely Causes

1. Out-of-Round or Broken 1-2-3-4-5-6 Clutch Snap Ring 🔴 High Probability This is a known manufacturing defect documented by GM in TSB #PIP5974E. It appears to be a design or material flaw in the 9-speed transmission used in the Blazer and its platform mates. TSB PIP5974A specifically identifies transmissions with a Julian build date between 23 274 and 24 113 (Oct 1, 2023 - Apr 22, 2024) as being highly susceptible.
   How to confirm: A transmission specialist must disassemble the transmission to visually inspect the snap rings. Finding significant metallic debris in the transmission pan is a strong indicator of this failure. The first step is to check the transmission's Julian build date to see if it falls within the affected range.
   Typical fix: The transmission must be removed and completely disassembled to replace the faulty snap rings and the entire clutch piston housing assembly as a kit. Often, a full remanufactured transmission replacement is the most practical and warrantied solution, per GM service strategy bulletin #20-NA-136.
   Est. part cost: $50-$200 for the ring/clutch kit itself, but thousands for a rebuild/replacement.
2. Failed Pressure Control Solenoid 'A' ⚪ Low Probability → Shop Transmission Valve Body While the solenoid can fail, it is an uncommon root cause for this specific vehicle and code. TSB #PIP5974E explicitly warns against replacing the solenoid or valve body as a fix for this code, as the problem is almost always the mechanical snap ring failure. It is often misdiagnosed as the primary fault.
   How to confirm: A technician can test the solenoid's resistance and function, but this should only be done after ruling out the snap ring issue. If the transmission fluid is full of metal, the solenoid is not the root cause.
   Typical fix: Replace the pressure control solenoid. This is located inside the transmission and requires removing the transmission pan and valve body. This repair is unlikely to be effective for this platform if the snap ring issue is present.
   Est. part cost: $50-$150
3. Low or Contaminated Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly
   How to confirm: Check the transmission fluid level and condition. The fluid should be red and clear, not dark, burnt-smelling, or full of metallic particles. Note that many modern transmissions like this one do not have a traditional dipstick and require a specific procedure to check.
   Typical fix: Perform a transmission fluid and filter change. If the fluid is heavily contaminated with metal, it is a definitive sign of the more serious internal snap ring failure mentioned above.
   Est. part cost: $100-$300

Rare But Worth Checking

• Faulty Valve Body: → Shop Transmission Valve Body Debris from a failing component can clog the small passages within the valve body, causing pressure issues even if the solenoid is functional. However, GM explicitly warns against replacing the valve body for this code on this platform.
• Wiring or Connector Issue: Damage to the wiring harness leading to the transmission or corrosion at the main connector can interrupt the signal to the solenoid.
• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly It is rare for the TCM to fail, but it can happen. This should only be considered after all other mechanical and electrical possibilities have been ruled out.

Diagnosis Steps

1. Check for any available TSBs for the vehicle's VIN. Pay special attention to #PIP5974E and its revisions.
2. Use a professional OBD-II scanner to confirm P0746 and look for other related codes like P0747 or P0700.
3. If possible, check the transmission's Julian build date. If it falls between Oct 1, 2023, and Apr 22, 2024, the snap ring failure is highly probable.
4. Check the transmission fluid level and condition. The presence of significant metallic debris in the fluid or pan is a strong indicator of internal mechanical failure.
5. A qualified technician should perform a transmission line pressure test to check the hydraulic pressure in the 1-2-3-4-5-6 clutch circuit.
6. If pressure is low and/or debris is found, the transmission must be removed and disassembled to inspect for internal mechanical damage, specifically the snap rings and clutch pack mentioned in TSB #PIP5974E.

Parts You'll Likely Need

• Transmission Assembly — Due to the high probability of a major internal failure (faulty snap rings), a complete transmission rebuild or replacement with a remanufactured unit is the most common and reliable fix. Independent shop estimates for replacement range from $4809 to $5189, while dealer costs can be $6946 to $7466.
  Trusted brands: ACDelco
  OEM price range: $3500-$5000
  Aftermarket price range: $2500-$4000 (remanufactured)
• 1-2-3-4-5-6 Clutch Piston Housing and Ring Kit (OEM #24277834 (example kit for platform mate)) — This is the specific set of components identified in TSB #PIP5974E as the required fix. The repair involves replacing the housing, piston, seals, and rings as a group. This is part of a full transmission overhaul.
  Trusted brands: ACDelco
  OEM price range: $100-$250
• Transmission Fluid and Filter Kit — This is required for any repair that involves opening the transmission, such as replacing a solenoid or the entire unit.
  Trusted brands: ACDelco
  OEM price range: $150-$250
  Aftermarket price range: $80-$150

Related Codes That Often Appear With This One

• P0747 — This code for 'Pressure Control Solenoid 'A' Stuck On' is the direct counterpart to P0746. Both are cited together in TSBs #PIP5974E and #PIE0720, as they relate to the same solenoid and underlying mechanical faults.
• P0700 — This is a generic transmission fault code that simply means the TCM has stored a specific code (like P0746) and has requested the check engine light be turned on.

Technical Service Bulletins (TSBs) & Recalls

• PIP5974E: Communicates that out-of-round transmission snap rings can cause code P0746 or P0747 and explicitly warns against replacing the valve body for this fault.
• PIE0720A: Notes investigation into vehicles that will not move and have set DTCs P0746 or P0747, confirming the severity of the issue.
• PIE0720: Predecessor to PIE0720A, initiating the investigation into the no-move condition with codes P0746/P0747.

Platform-Specific Known Issues

• TSB #PIP5974E documents an issue with out-of-round 1-2-3-4-5-6 snap rings causing codes P0746 or P0747.
• TSBs #PIE0720A and #PIE0720 confirm that these codes can lead to a severe no-move condition in Drive or Reverse.
• TSB PIP5974A specifies a high-risk production window for transmissions built between October 1, 2023, and April 22, 2024.
• Owner experiences on forums like Reddit report this failure happening on brand new 2024 Blazers with less than 100 miles, resulting in a complete loss of acceleration.

Mechanic-Grade Diagnostic Values

• Pressure Control Solenoid Coil Resistance — expected: 5 to 30 Ohms. Failure: A reading of infinite ohms (open circuit) or near-zero ohms (short circuit) indicates a failed solenoid coil.

Scan Tool Commands That Help

• GM GDS2 (or equivalent professional scan tool): Active Test / Solenoid Actuation — To command the Pressure Control Solenoid 'A' on and off manually. A response (like a click) helps confirm the solenoid's electrical circuit and coil are functional, separating an electrical fault from a mechanical (stuck) or hydraulic issue.
• GM GDS2: Transmission Service Fast Learn — This procedure should be performed after any major transmission repair, such as replacing the valve body, solenoids, or the entire transmission assembly. It resets and relearns the transmission's adaptive pressure values to ensure proper shift quality.
• GM GDS2: Monitor Commanded vs. Actual Gear State — During a test drive, a technician can monitor the gear the TCM is commanding versus the actual gear ratio calculated from speed sensors. A mismatch when commanding a gear that uses the 1-2-3-4-5-6 clutch is a key condition for setting P0746.

Wiring & Ground Locations

• Fuse F58 — Engine Compartment Fuse Block. This fuse supplies power to the Transmission Control Module (TCM). A blown fuse would result in a loss of control over all transmission functions, including the pressure control solenoids.

Real Owner Repair Stories

• Reddit user in /r/MechanicAdvice (2024 Chevrolet Blazer RS) — Vehicle would not accelerate properly; engine revved to 6,000 RPM while only going 12 MPH. Failure occurred with less than 100 miles on the odometer.
  ❌ Tried (didn't work) N/A, vehicle was taken directly to the dealership.
  ✅ What actually fixed it The vehicle was taken to the dealer for warranty repair. While the final fix isn't posted by the original author, the symptoms are identical to the known TSB issue regarding internal snap ring failure, which requires transmission replacement or overhaul. Other users in the thread confirmed identical failures on their new 2024 Blazers.
• YouTube video by Gary Ferraro (Transmission Specialist) (2018 Chevrolet Traverse with 9T65 Transmission (90,000 miles)) — No reverse gear engagement. Forward gears worked. No trouble codes were stored.
  ❌ Tried (didn't work) N/A, diagnosis went straight to internal inspection based on symptoms.
  ✅ What actually fixed it The transmission valve body was removed, revealing that a checkball had been forced through its seat in the separator plate, causing a complete loss of hydraulic pressure for the reverse circuit. The fix was to replace the damaged valve body separator plate, which resolved the no-move condition without requiring a full transmission overhaul.

When the Usual Fixes Don't Work

• While the authoritative TSBs point to the snap ring failure as the primary cause of P0746, requiring a full teardown, other documented failures within the 9T65 transmission can produce similar 'no-move' symptoms with a much simpler fix. For example, a known issue is a checkball blowing through the valve body separator plate, causing a loss of reverse. This requires only removing the valve body and replacing the plate, a significantly less intensive repair. A technician should inspect the separator plate for damage before committing to a complete transmission overhaul, even when P0746 is present.

Model Year Variations Within This Range

• 2018-2021: Per GM bulletin #20-NA-136, the official service strategy for internal 9T65 transmission faults was updated. Instead of performing complex internal repairs, dealerships were directed to replace the entire transmission assembly to reduce vehicle downtime and ensure a quality repair.
• 2022-2023: A recall was issued for some Blazers within these model years due to the installation of a dimensionally incorrect sun gear (part #24290255) at the assembly plant. This could cause the driver-side half-shaft to disengage, leading to a loss of propulsion or a rollaway condition.