EGR flow excessive on VAG TDI — carbon-locked EGR valve or failing EGR position sensor.
Volkswagen P0402 — EGR flow excessive on VAG TDI — carbon-locked EGR valve or failing EGR position sensor. Typical UK independent garage cost: £250–£950.
What actually causes P0402 on a Volkswagen
EA189 TDI: post-dieselgate software increased EGR duty cycle to reduce NOx and the valves clog faster. We see them stick open with a partial carbon film — flow is high, position sensor reads midway. EA288 is better but not immune.
Volkswagen engines that log P0402
- 1.6/2.0 TDI EA189 (Golf, Passat, Tiguan)
- 2.0 TDI EA288 (Golf 7, Passat B8)
- 1.9 TDI PD (older Golf, Passat)
How we diagnose P0402 on a Volkswagen
- VCDS block 74 — EGR commanded vs actual position
- Remove EGR, bench-clean with carb cleaner
- Position sensor resistance check across the range
- Clean intake manifold — swirl flap area is worst
The common misdiagnosis to avoid
Cleaning the valve with the throttle body cleaner in situ — you'll wash carbon into the intercooler. Remove, bench-clean, inspect the position sensor separately.
Volkswagen P0402 repair cost in the UK
Expect £250–£950 including parts and labour at an independent garage. Main-dealer quotes on Volkswagen 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
EA189 Golf/Passat — factor in a manifold clean when quoting. Manifold-off is the only proper fix.
Codes usually seen alongside P0402 on Volkswagen
- P0401
- P0403
- P0404
- P042F
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.