Volkswagen P0402

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

1. VCDS block 74 — EGR commanded vs actual position
2. Remove EGR, bench-clean with carb cleaner
3. Position sensor resistance check across the range
4. 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.

Reading P0402 on a Volkswagen properly

A generic reader will show P0402 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the Volkswagen has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.

Clearing P0402 without fixing it

Erasing the code resets the Volkswagen's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.

Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0402 is showing on your Volkswagen, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.