The wifes A6 has a engine light on Solenoid Valve for Boost Pressure Control

[iain120]

Dear all who can help!

The wife has our trust A6 2005 2.0 TDI in for MOT today, and thankfully it passed, better still with no advisories!

However, upon picking it up she noticed the EML light on. She went back in and they said this was there before they did the MOT. Something I don't believe as would it not have failed having the EML light on before the test??

No the less, it's on now and they are having none of it.

Thinking it might be a misfire or something from all the revving they did in the garage I plugged it into VCDS to take a look. I get only one fault code, which surprises me! It is:

16627 - Solenoid Valve for Boost Pressure Control (N75)
P0243 -000 - Malfunction
Freeze Frame:
RPM: 2394 /min
Torque: 166.0 Nm
Speed: 74.0 km/h
Load: 45.5 %
Voltage: 13.91 V
Bin. Bits: 00001000
Absolute Pres.: 1927.8 mbar
Absolute Pres.: 1468.8 mbar

I've tried the usual clear the DTC, but it comes back, even when the engine isn't running.

Now my suspicions is the N75 valve, but reading on here someone said there was a 1% chance it was that... If I'd got a ton more errors I would be included to agree, but having only the one, I'm hopeful it's that or a bad wire.

Does anyone have any ideas, they would be welcome. Also if anyone knows the N75 location on the 2.0tdi that would be great, I don't have ETKA on my new laptop sorry!

Many thanks,
Iain

[Rob69]

If the light was on before or during the test then i would have thought that would be flagged as an advisory, afaik it is not a failure to have the light on during the test. Anyway, i'd do some checks of boost required vs boost actual with vcds to see what the n75 and turbo are actually doing, has the engine not gone into limp mode? On my b5 passat the n75 is next to the air filter on the inner wing, or on the front of the engine, sorry cant remember which is n75 and n18, but if you follow the vac hose you shoul find it.

[iain120]

Hi, thanks for the reply. I've had a look this morning and taken the car for a drive, the EML light is off, and hasn't come back, but the car is 100% in limp mode. The N75 fault comes back even with the engine off, so i'm really hoping it's just that.
I've taken a look at the part, or what I think it the part and the wires and pipes all look good. The rod to the turbo from the vac unit moves and all the pipes look in good nic.
Before I spend my weekend trying to fix it does anyone else have any suggestions?

[iain120]

34135

Ok, so an update. Got the boroscope camera out and it looks like a wire... Nice I've found it, pain in the butt its broken!

[Rob69]

Happy days, hope its sorted now

[dan2485]

You can get repair wires with a pin/socket attached or just get a new pin a attach it to the existing broken wire, then put it into the plug.

There are a few good videos on YouTube for the pin extraction of VAG connectors.


Pins and plug are available on Ebay also.