EGR flow excessive on Audi TDI — same EA189/EA288 carbon issue as VW, plus 3.0 TDI CR EGR cooler failures.
Audi P0402 — EGR flow excessive on Audi TDI — same EA189/EA288 carbon issue as VW, plus 3.0 TDI CR EGR cooler failures. Typical UK independent garage cost: £280–£1400.
What actually causes P0402 on a Audi
2.0 TDI: identical to VW — carbon-locked EGR valve. 3.0 TDI CR (V6 diesel): EGR cooler cracks internally and floods the intake with unmetered gas — sets P0402 with MAF discrepancy.
Audi engines that log P0402
- 2.0 TDI EA189 (A3, A4 B8, A6 C7)
- 2.0 TDI EA288 (A3 8V, A4 B9)
- 3.0 TDI CR (A6, A7, Q5)
How we diagnose P0402 on a Audi
- VCDS block 74/75 — EGR position and MAF flow
- Remove EGR valve, bench-clean and inspect seat
- 3.0 TDI CR: pressure-test EGR cooler
- Clean manifold, fit Pierburg OE valve
The common misdiagnosis to avoid
3.0 TDI CR — replacing the valve without inspecting the cooler wastes £400. Always pressure-test the cooler on V6 diesel.
Audi P0402 repair cost in the UK
Expect £280–£1400 including parts and labour at an independent garage. Main-dealer quotes on Audi are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.
Bob's workshop tip
A6 3.0 TDI — always pressure-test the EGR cooler before condemning the valve.
Codes usually seen alongside P0402 on Audi
- P0401
- P0403
- P042F
- P244A
Symptoms drivers report with P0402
- Rough idle, often shaking the gear lever
- Hesitation off the line
- Stalling at junctions
- Possible black smoke at idle
- Engine warning light + power reduction warning
Repairs that clear P0402
- EGR clean or replace
- Sensor inspection
For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0402 guide.