P172A on Audi: How to Diagnose & Fix
Auxiliary Transmission Fluid Pump Reverse Rotation
1 Audi model · 1 documented issue · 1 critical · $1,200-$2,800 repair
P172A on Audi by model: symptoms, diagnosis and fix
A1s fitted with the 7-speed dry-clutch S tronic (DQ200, VAG code 0AM) automatic suffer mechatronic (valve body / hydraulic control unit) failures. A design flaw in the valve body's accumulator/canister wall can crack and lose high hydraulic pressure, while the dry clutch packs wear and cause juddering. This led to Audi recall campaigns for the pressure accumulator (e.g. 35D9 in October 2019 and follow-up 35E7 in May 2020 for 2011-2016 model-year A1s with the 7-speed S tronic, as published in Australia); eligibility in other markets must be checked by VIN. Failure can cause sudden, complete loss of drive.
Common Symptoms
- Judder / harsh 1st-to-2nd shift at low speed
- PRNDS / gearbox warning flashing on dash
- Erratic or jerky gear changes
- Sudden loss of drive or no drive
- Limp-home mode
How to Fix
Recondition or replace the mechatronic unit with the superseded/uprated valve body, update the transmission control software, and inspect/replace the clutch pack if worn. Check the recall has been completed on any used purchase. Regular DSG service (fluid for wet-clutch variants) helps; the dry DQ200 valve body fix is the core remedy.
Sources for this issue (2)
P172A 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 P172A mean on a Audi?
P172A stands for "Auxiliary Transmission Fluid Pump Reverse Rotation." P172A is a manufacturer-specific powertrain code (most commonly seen on Subaru CVT-equipped vehicles) indicating that the auxiliary (electric) transmission fluid pump is rotating in reverse. The auxiliary pump maintains transmission/CVT fluid pressure, so reversed rotation reduces hydraulic pressure and can cause shifting and engagement problems. The transmission control module sets this code when it detects the pump is not turning in the commanded direction. On Audi it is documented across 1 model: A1.
What are the most common causes of P172A?
The most common causes of P172A are: Faulty auxiliary (electric) transmission fluid pump or its motor, Leaking O-ring on the electric oil pump relief valve allowing CVT fluid into the pump motor, Damaged, corroded, or shorted wiring/connectors to the auxiliary pump, Faulty pump control module or transmission control module (TCM), Low or degraded transmission/CVT fluid. The specific cause varies by vehicle.
How much does it cost to fix P172A on a Audi?
Published repair estimates on Audi range from $1,200 to $2,800 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 P172A on a different make?
View P172A across all makes →Join 600+ people using Au7o to better understand their vehicles.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.