17964 VCDS code

[nbat58]

My car was running fine for 5 days after an second hand turbo fitted with 70000 on the clock, without warning all of a sudden no boost whatsoever, no limp mode, just no boost at all.

I have changed all the VAC lines with new original genuine hose, but still no boost.

 

I have disconnected the actuator pipe N75 sensor end and cycled the N75 with VCDS while feeling for vacuum, vacuum was present but not sure whether it was high enough as I haven't got a mini vac.

 

I didn't have time to mess about with it too much so I have taken it to my local indie and he reckons, it needs a new turbo as there was no boost at all and the turbine shaft may have broken.

 

I was hoping for a sensor or electrical boost pipe fault as the turbo had no indication of any limp mode or anything prior to this.

 

I have checked the MAF sensor with VCDS, not sure about the MAP sensor though, I have a spare that I can try to see if there are any changes but not sure where this is situated in the 1.9TDI ASV engine.

 

I thought that a sensor or the turbo breaking would mean I get limp mode? I am not getting limp mode at all just no boost with VCDS code 17964.

 

Many thanks for any suggestion on what to try next or whether it is worth taking to a vag garage, the indie today charged me £50.00 for his diagnosis.

 

[Guest]

I pulled this from Ross tech. Might shed some light on it.

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17964/P1556/005462

Contents [hide]

1 17964/P1556 - Charge Pressure Control: Negative Deviation

1.1 Possible Symptoms

1.2 Possible Causes

1.3 Possible Solutions

17964/P1556 - Charge Pressure Control: Negative Deviation

Possible Symptoms

Reduced power output

Limp mode

Possible Causes

Boost Pressure too Low

Hoses/Pipes incorrect connected, disconnected or leaking

Charger Pressure Control defective

VNT (variable nozzle turbo): nozzles stuck

Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions

Check Hoses/Pipes to/between Components

Check Solenoid Valve for Boost Pressure Control (N75)

Check / Clean / Replace Charge Pressure Control

Check / Clean mechanism for variable nozzles

Category: Fault Codes

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Common Procedures

Fault Codes

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[kentphil1]

For info - http://wiki.ross-tech.com/wiki/index.php/17964/P1556/005462 - may help

[nbat58]

I have changed all the VAC hoses, checked the N75 and that was ok, the only thing I haven't done is check the charge pressure, anyone know how this is done and where the charge pressure control is.

Many thanks.

[Bjornm]

It is done by the CPU, by all those little sensors and pressure valves and things.

You cannot adjust it yourself.

In my Octavia, with similar problems, , I cleaned the MAP (first thing after the air cleaner in the inlet tract). I took it out, sprayed it carefully with brake cleaner, and immersed it in denaturated alcohol in a plastic bag and then let it dry (blew GENTLY with pressurized air - the thing is BRITTLE).

My car responded very well to this.

It is also possible that a clogged up EGR-valve (mine was horrible) and inlet manifold, also possibly clogged up, needs cleaning. Oil from the crancase vent gets into the inlet air and deposits by help of said EGR-valve as a thich sooty layer in these parts.

The intercooler (well hidden under the screen washer fluid container and headlight, may also need to be cleaned from oily deposits (mine will tomorrow).

Lastly, sooting up of the turbo is also possible (likely) cause. 

Can be cleaned with Revive cleaner or,, with a little taking down of parts, with oven cleaner.

Search the forum for YouTube vidos and explanation.

 

Go buy yourself a Haynes manual - wort absolutely every penny! (If you don't already have one - I cannot praise the thing enough!)

 

Good luck, buddy!

Edited 30 November, 2014 by Bjornm