Help diagnosing ECU Fault code 16618

[Big_Mikey_G]

Hi Guys,

Recently ive been having some problems with my Ref Sport TDI 140.

Its lost some power and the fuel economy is down from about 450 miles per tank to 400!

Most worryingly of all though is that above about 3000rpm, the car has been going in to limp mode!

Have logged a fault code on the ECU, 16618 - Pressure overboost.

I was expecting it to be the Mass Air Flow censor that was malfunctioning and causing the turbo to over boost thus putting it into limp mode.

Took it to the garage yesterday. They say its not the Mass Air Flow but the whole turbo that needs replacing.

Would like a second opinion on this to make sure the garage isnt just ripping me off.

Have checked out Ross Tech Wiki for the fault code and this is what it returns.

http://wiki.ross-tech.com/wiki/index.php/16618/P0234/000564

16618/P0234/000564 - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)

Possible Symptoms :

Boost pressure too high
Reduced power output

Possible Causes :

Hoses incorrect connected, disconnected, blocked or leaking
Malfunction N75

Possible Solutions :

Check charge pressure control
Check Solenoid Valve for Boost Pressure Control (N75)


Any ideas please gents?!

Thanks,

Mike

 

[rudgey]

Ermmm well if you haven't messed with the pipe work at about the same time the fault appeared, i'd say going by the ross tech info that the n75 valve is at fault? However i'm no mechanic, so i'd try taking it to another garage!

 

[Big_Mikey_G]

Nope, havent touched the pipe work at all. Exactly as i bought it!
Solenoid valve is a probability but i dont know if they'll replace this part without replacing the whole turbo. Most garages these days are just technicians who do what the machine tells them as opposed to mechanics. I might give Awesome a ring and see what they say about the fault code.

Mike