Engine power issue - diesel warning light

[DavidWNE]

Hi,

I'm looking for some advice please on what the issue could be with my T6.1 T28 manual engine.

The van is just over 2 years old, done 14k miles and it's developed an intermittent fault.

I first noticed it last month when I was driving back from lakes (over 90 miles). The diesel engine management warning light started flickering, and I noticed a significant drop in power (not limp mode but certainly went through the rev ranges much slower and reluctantly).

I initially put it down to the DPF so gave the van a good blast which i hoped would solve it, but it seems that it is now becoming an issue on every long drive, off and on, throughout the journey. I've noticed it happens more if I'm driving in a low rev range for a short period, followed by a period of acceleration.

The van is still under warranty so would look to put it on a diagnostic, but would the fault still show in some form of log if it's not showing at the point its plugged in? It only flashes for the period I am revving and then drops off again.

Thanks in advance for any pointers or suggestions as to what it could be.

Cheers
David

 

[bluezie]

Yes, any fault that has triggered a dashboard light will have it logged in the relevant ECU with other data such as time and date and frequency of the fault etc.

 

[DavidWNE]

Yes, any fault that has triggered a dashboard light will have it logged in the relevant ECU with other data such as time and date and frequency of the fault etc.

Great thanks for confirming. I've ordered a Carista OBD scanner and going to check it's nothing to do with the conversion before taking it in to VW.
Thanks!
David

 

[DavidWNE]

OK so I've just ran a diagnostic test using a Carista and I'm surprised by the results.. nothing mechanical at all.

i have two recutring fault codes 16777020 - 'function restriction due to service communication interruption'. (9 instances). The radio has always been a little unreliable since new, which I think this code may be related to?

Second one is 263442 - Sirens / alarm horn for anti-theft warning system: No
release by immobilizer (259 instances!).

Surely neither of these can be the cause of the mid-journey loss of power / diesel warning light being triggered? Or could it be?!

Not sure where to go from here as I'm mindful I don't want to get ripped off if I go to the main dealer and they can't find anything, or if in fact its some of my dodgy wiring that needs rectifying before taking it in to the garage.

Final question - if I reset the fault codes would it be visible to the main dealer and if so would it void my warranty?

Thanks!
David

 

[DavidWNE]

Hi, so I've reset the fault codes a couple of times and these two faults reappear immediately after I restart the engine.
I've had the van on long journeys so that the diesel warning light shows (which is the real problem), checked the carista immediately after and no fault codes relating to the engine show.
Before I take it into VW I was hoping to figure out what the two electrical fauls may be. Does anyone have any idea what could be causing them?

Thanks in advance for any assistance!
David