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Audi Q3 F3 2018+ DQ381 DSG Mechatronic Repair — Fault Codes P173500 & P173600

The Vehicle Check offers a specialist mail-in DQ381 DSG mechatronic repair for the Audi Q3 F3 (2018 onwards), addressing fault codes P173500 and P173600, with a 3–5 working day turnaround and free tracked return — available UK-wide and internationally. View the live listing here.

When your Audi Q3 F3 starts lurching between gears, dropping into limp mode, or flashing a gearbox warning on the dash, the fault scanner often returns codes P173500 or P173600. These codes point squarely at the DQ381 mechatronic unit — the combined hydraulic and electronic control block that sits inside your DSG gearbox. It manages pressure, solenoid valve switching and clutch pack engagement in real time, and when it starts to fail you feel it immediately: hesitation pulling away, harsh or delayed shifts, and sometimes a refusal to move out of a single gear at all. The good news is that the unit itself is repairable, and you don't need a new gearbox to fix it.

Quick Facts

What do fault codes P173500 and P173600 actually mean?

P173500 and P173600 are DQ381-specific codes that the gearbox control module logs when it detects abnormal behaviour from the mechatronic's internal solenoid valves or pressure-regulation circuits. The mechatronic unit is essentially the brain and hydraulic heart of the DSG rolled into one assembly — it controls precisely when and how hard the clutch packs engage. When the solenoids or the valve body develop faults, the control module can no longer trust the feedback it's getting, so it protects the gearbox by limiting operation. That's the limp mode you're experiencing. Clearing the codes without addressing the underlying mechatronic fault will only bring them back.

Is mail-in repair a realistic alternative to a dealer or gearbox specialist?

For most owners, yes — and it usually works out significantly more practical. Here's an honest comparison:

How do I check whether part numbers P173500 or P173600 match my unit?

P173500 and P173600 are unit-family reference numbers that cover the DQ381 mechatronic fitted to the Audi Q3 F3 from 2018 onwards. The specific number printed on your mechatronic's own label may differ slightly within that family. Before sending, check the label on your unit and note the number — TVC will verify compatibility when they receive it and will contact you if anything needs clarifying before work starts. If you're unsure before posting, call 0203 489 2610 and the team will talk you through it.

How do I remove and safely pack the DQ381 mechatronic for posting?

The mechatronic unit is bolted to the DSG gearbox housing and connected by a wiring harness; removal takes a competent DIYer or independent garage about an hour. Once off the car, follow these packing steps to protect it in transit:

• Drain any residual transmission fluid from the unit before packing — wrap the connector ports with cling film or tape to avoid leaks in the box.
• Wrap the unit in at least two layers of bubble wrap, paying attention to the solenoid connector block.
• Place it in a rigid cardboard box with foam or screwed-up paper packing on all sides — the unit should not be able to move when you shake the box.
• Include a note with your name, return address, vehicle registration, and the fault codes you've had (P173500 / P173600).
• Use a tracked courier service and keep the tracking reference until your repaired unit is back and fitted.

Send to: Office 13, 25 Mollison Avenue, Enfield, EN3 7NJ.

Why trust The Vehicle Check with your DQ381?

The Vehicle Check is a UK automotive electronics specialist with hands-on experience across the full range of VAG DSG mechatronic units — DQ200, DQ250, DQ381, DQ500 and beyond — as well as Mercedes 9G-Tronic mechatronics, Honda engine ECUs, SRS airbag modules and much more. The team bench-tests every mechatronic unit before it goes back in the post, so you know the unit has been verified functional — not just worked on and hoped for the best. That bench-testing process, carried out at the Enfield workshop, is something a general garage simply cannot replicate without specialist equipment. The result is a repair you can trust to go straight back into the car without second-guessing.

Explore the full range of mechatronic repair services, or browse related services including clutch actuator repairs, BCM, BSI and FRM cloning, and crash data and airbag module reset.

Frequently Asked Questions

Ready to get your Audi Q3 F3 shifting properly again?

Order the DQ381 mechatronic repair online and post your unit to The Vehicle Check — the team will have it bench-tested, repaired and back on its way to you within 3–5 working days, with free tracked return included. If you'd prefer to talk it through first or want to confirm your part number before sending, call 0203 489 2610. Lines are answered by people who know these gearboxes, not a call centre.

The Vehicle Check is a UK automotive electronics specialist at Office 13, 25 Mollison Avenue, Enfield, EN3 7NJ, offering nationwide and international mail-in repair and cloning. Call 0203 489 2610. Last updated: 14 November 2026.