Volkswagen Passat - Turbo failure? - Chrisr

My 2006 Passat 2.0i often reverts to get-you-home power level. Last week, on a long trip, it started out OK, then the power cut down, the engine management light came on and the glow-plug light was flashing. Stopping the engine re-set the power (management light stayed on) but the glow-plug and power drop could happen a few seconds or minutes later. On the return journey, the management light was on but the power was OK, under gentle or hard driving. Re-starting after a short tea break, the management light was off and power was OK. My local dealer has recommended a new turbo but these symptoms don't seem to me to be because the vanes are sticking. Has anybody had a similar problem?

Volkswagen Passat - Turbo failure? - unthrottled
2.0i? Can we confirm that it is diesel?

There are lots of threads on 'broken turbos'-basically any loss of power is initially blamed on the turbo. Of course the turbo needs a certain amount of exhaust enthalpy to spool. If the engine management pulls fuelling it won't spool. The actual turbo only has one moving part and rarely fails. If it does, it is noisy and not intermittent. You need to get the fault code read.
Volkswagen Passat - Turbo failure? - Chrisr

My local dealer found fault codes for g31 and g42. They have changed the G31 sensor and I think they have run out of ideas, so they suggest changing the turbo @ around £1,400. I can get one half that price from Turbo Technics. The car has had this problem since new - not often in the early days but a lot now - 148,000 miles. I cannot understand, when restarting the engine solves the problem, why should the management light stay on? And why should the glow-plug alarm light come on (with the power loss) if it is a turbo problem?

Can anyone recommend a top independent specialist? I am prepared to travel anywhere to solve this>

Many thanks.

Volkswagen Passat - Turbo failure? - injection doc

the variable vane turbo's do suffer with sticking vanes and can be stripped and cleaned. We have a local Audi specialist who does these almost daily ! Martin 01225790890

In america its common to clean them with oven cleaner in situ!

Volkswagen Passat - Turbo failure? - craig-pd130

It sounds like it's overboosting, which usually suggests a problem in the vacuum system that controls the VNT mechanism .... the solenoids which control this can and do fail.

Or it could be a leak in the vacuum pipework which is causing erratic boost control, which again would put the engine in limp mode.

Any stored fault codes may be misleading, they tell you the symptom but often don't identify the true cause .... which is why dealers often simply say "new turbo"

Volkswagen Passat - Turbo failure? - unthrottled
This is true. But if you get an overboost error code-it's pretty much a given that the wastegate/vanes have stuck since there is not much else that could cause a turbo to overspeed.

But there are other reasons that could cause the ECU to pull fuellling back to limp home levels that are not turbo actuator related. Error codes give you a starting point for a proper investigation. Although Dave the sales manager is not likely to conduct that investigation. 'Hmm, lets assume that it's the most expensive part, and we'll go from there...'
 

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