MPG dropped drastically last 2 weeks

[FRozz]

Since I got my FR 2.0 TDI in September I have averaged around 42mpg, about 48mpg with slow driving and 37 when thrashing it. For the past couple of weeks I have not managed over 41mpg, and that was with cruising at about 40mph in 5th and deliberately trying to get good mpg. Normal driving is now around 37mpg, driving the same route to work as always.

I have ran a few scans with VagCom since I got it and have always got the following error

1 Fault Found
008194 - Particulate Trap Bank 1: Efficiency Below Threshold
P2002 - 006 - Short to Plus - Intermittent
Freeze Frame:
Fault Status: 00010001
Fault Priority: 1
Fault Frequency: 2
Reset counter: 40
Mileage: 43809 km
Time Indication: 0
Date: 2000.00.00
Time: 07:47:33

Freeze Frame:
RPM: 1952 /min
Torque: 192.0 Nm
Speed: 23.0 km/h
Pressure: 0.0 mbar
Text: -21 mbar
Text: 176 C
Temperature: 7.5°C

Readiness: N/A

Could this be the cause? Does anyone know what it means? I have asked on the VagCOm thread but no response. I imagine it has something to do with dpf but not sure what exactly.

 

[FRozz]

Another thing I considered is a fuel filter change. Not sure if this was done at the last service.

 

[GainfulShrimp]

I'm no expert, but it looks like a DPF related fault code, I agree.

On the mpg loss... has it been a lot colder where you are over the past two weeks? I noticed quite a dramatic drop in mpg over the very cold spell we had late last year. Because the engine takes so long to warm up when it's really cold, you do most of the journey with a below-temp engine, which is much less efficient.

Also, if your car is doing regen for the DPF (sometimes noticeable as idling at ~1,000rpm and slightly sluggish driving), your mpg figures will suffer during that too. Just an idea.

 

[FRozz]

It definitely isnt the colder weather, I was still getting decent figures when the temp dropped to -14C in November, its been around 4C for the past few weeks.

Im sure a regen only takes 10-20 mins, this has been going on for a couple of weeks and the engine still feels great.

One other possibility is that I started adding millers fuel additive, will not use it the next fillup and see if I get an improvement.

As for my error code, does anyone know what it means?? Is it a bad sensor, dpf failure, etc...

Cheers

 

[kassim]

Change the following

Fuel filter

Air filter

and also clean the MAF sensor

 

[sorin83]

You might also want to take off the whinter tyres if you still have them on.