code 17964

[stevievegas]

Hi,

Just bought a Seat Leon Mk1 1.9Tdi 2004 plate.

About 40 mins after buying it I was driving down the motorway and the engine diagnostic light came on and lost power. Took it back to the father in laws garage and his mate ran vag com check and it came back with code 17964 (charge pressure control: negative deviation). Turned the code off and he did some checks on the car and everything looked fine. Drove off and was fine for about 30 miles and then the light came back on (again, on the motorway in 5th doing about 70). It used to be driven by an old man and has 50k on the clock.

I previously had a Ford Focus 1.8TDi and the Leon feels a lot heavier and slower when accelerating. When it finally gets to 70ish it's fine at cruising.

I've unplugged the MAF sensor and driven it 30 miles on the motorway and seems fine.

I'm going back up to see him in the next week or so. Was just trying to help him diagnose the fault before I replace MAF sensor, N75 and N17.

Car seems fine 1st, 2nd, 3rd and 4th. Just when it gets into 5th I feel it cut back on the power and then the engine light comes on.

Any advice would be much appreciated.

cheers

 

[stevievegas]

I was also wondering if it could be a build up in the turbo causing it to stick as the previous owner didn't do much more than potter round in it

 

[S10EAT]

Negative Deviation is not enough boost pressure.

Could be sticky vanes or a boost leak on one of the intercooler pipes.

That's where I would first start looking.

If it's not sticky vanes could be a faulty actuator.

Was performance better with the MAF unplugged?

If it was I would replace it.

 

[stevievegas]

Cheers. There's a few pointers there to look at.
I've unplugged the maf sensor and cleared the open circuit warning.
I've not had the engine warning light come on or noticeable loss of power when accelerating but it still seems slow when on the motorway in 4th and 5th

 

[S10EAT]

If you have an open circuit warning you either A I would start with some contact cleaner on the MAF sensor connector, and some isoproyl alcohol to spray on the MAF sensor itself inside.

If this does not solve the issue, replace the MAF.

I've had the short/open to ground error before and was a faulty MAF.

 

[S10EAT]

Both spray cans can be obtained from a shop like Maplin Electronics.

 

[stevievegas]

Thanks for that. I created the open circuit myself though as I've removed the maf sensor for testing. Whilst I don't get the engine slowing when it's not connected, it still seems really slow when accelerating on the motorway. I've seen 1.4's overtake me. That's why I'm thinking it might be sensor related and might be something else too. I'll try and clean the sensor this weekend and see if the father in law can strip the turbo and see if it needs cleaning

 

[sssstew]

negative deviation means its getting less boost than it expected, so its loosing boost somewhere, usually down to a boost leak. are you seeing any extra smoke?

 

[stevievegas]

a small amount of whitey/grey smoke when setting off from cold start but nothing worth mentioning. father in law spoke to a seat dealership mechanic and he reckons it sounds like the actuator is at fault. presume only way to test this is vag com?

 

[sssstew]

you can do a test of it with VAG COM, muddyboots has previously posted the steps for this, have a search.

Strange that your not seeing extra smoke. I would get vag com and log boost requested vs actual and see whats actually happening.

 

[stevievegas]

it was a problem with a small (tiny) hole in the hose going from the N75. replaced it and boosts fine now

only problem i've got now is that when it starts from cold it goes about 20 yards and then completely shuts down. i then have to start it again and it runs fine. not sure if this problem is related as its only happened now that hose has been fixed.

anyone any ideas on what to look for? air block maybe?

 

[sssstew]

strange. does anything get logged for this shut down?

 

[stevievegas]

unfortunately no codes showing up. not sure if the hose that we cut down a bit on saturday to fix the turbo boost might have caused the problem. it's the only thing that we changed. maybe just need to put a completely new length of hose on?

 

[sssstew]

very much doubt it will be because of the shorter hose. But cannot provide any suggestions as to why it might be occuring though sorry....

 

[stevievegas]

i meant that the hose could be damaged somewhere else and might just replace the hose instead of taking out the piece with the tiny hole in. going back to garage on friday morning to get looked at although this morning it started fine