Hi,

 

I hope you’re all well and apologies if this topic has already been covered.

 

My 2014 VRS diesel (CUPA engine) is suffering a problem where the power suddenly drops off and the revs also drop to idle. After just a moment it will pick up again slowly. 
 

It’s an auto (DSG box) and the sensation when it happens is pretty violent. The clutch pack was replaced last year and there are no noises or problems selecting any gear.

 

The issue happens mostly when pulling away or accelerating hard but can also be when you’re just cruising along at any speed (although this has been pretty rare).

 

No warning lights have appeared nor any faults stored. I have had the fuel filter changed but unfortunately this hasn’t made any difference. I have read elsewhere that it might be the fuel pump relay which I will also try but just wanted to find out if anyone else has had this issue and what the fix was?

 

All the best,

 

Joe

Is it at a particular rev range or at any point?

 

You say no fault codes are stored, but is the car going into limp home mode or just dropping then surging?

Hi,

 

Thanks for replying. It seems to happen about mid to high range and it suddenly drops almost as if your foot has slipped off the throttle and then builds back up again. It doesn’t go into limp home mode at all.

 

I’ve had it checked with the relevant vagcom diagnostic software and nothing comes up.

 

Hopefully this helps but please do let me know if there’s any more information I can provide.

 

All the best

Hello Joe

 

Always difficult to diagnose over the interwebnet.

 

I had similar on a diesel Passat (standard autobox) and it turned out to be a faulty brake pedal switch.  Fly by wire, so when the brake was 'applied' it killed the throttle - the brakes weren't being applied but the internal switching was faulty so the car thought I was braking.

 

Just a thought - could be lots of things.

 

Gaz

Try changing the fuel filter, I had the same issue on a 200ton crane I was trying to load onto a cargo ship, could not get full power as the filter was blocked, replaced it and all was good 🙂

On 26/06/2020 at 18:25, IamGaz said:

Hello Joe

 

Always difficult to diagnose over the interwebnet.

 

I had similar on a diesel Passat (standard autobox) and it turned out to be a faulty brake pedal switch.  Fly by wire, so when the brake was 'applied' it killed the throttle - the brakes weren't being applied but the internal switching was faulty so the car thought I was braking.

 

Just a thought - could be lots of things.

 

Gaz

That’s a great idea, thanks for the suggestion. I’ve ordered up a new switch so fingers crossed that’ll do the trick.

32 minutes ago, jjc said:

Try changing the fuel filter, I had the same issue on a 200ton crane I was trying to load onto a cargo ship, could not get full power as the filter was blocked, replaced it and all was good 🙂

Thanks, that was my initial thought as well. I’ve had that changed and it’s made no difference unfortunately.

On 26/06/2020 at 18:25, IamGaz said:

Hello Joe

 

Always difficult to diagnose over the interwebnet.

 

I had similar on a diesel Passat (standard autobox) and it turned out to be a faulty brake pedal switch.  Fly by wire, so when the brake was 'applied' it killed the throttle - the brakes weren't being applied but the internal switching was faulty so the car thought I was braking.

 

Just a thought - could be lots of things.

 

Gaz

Hi Gaz,

 

I’ve changed over the switch (serious pain go get to!) and unfortunately it’s not made a difference. Any other suggestions would be greatly appreciated.

 

all the best

Has the car been scanned for any fault codes. Even intermittent there will be a code stored on the ecu.

Thanks, see above. I’ve had it checked out (twice now) and no fault codes are stored 

Just wondering if you ever solved this problem??? I am having very similar problem. Usually happens within the first 10min. Will lose power suddenly. When accelerator release and pressed again move slowly through the gears. When turned off and on again it drives ok again until parked up for several hours. Then same problem again

I had the same problem with my 2014 vrs diesel. Drove me mad for ages. Like the previous posts, it was quite violent when it happened. Almost like you were pressing the brake on/off. Was going on for months, and eventually a fault showed. Turned out to be the crank shaft sensor. Replaced it with genuine part and never happened again. 

Thanks. A fault eventually showed up as a fuel sensor. Change the fuel sensor and it seems to have sorted the problem. Hasn't happened in over a week