I hope someone can help with this please. I have had this 17544 fault code for about 18 months now (Bank 1 system too lean). As the car runs OK even after the engine management light comes on I haven't bothered to do anything about it until recently. Mpg dropped off a bit so I replaced the front O2 sensor thinking that this would resolve it. Well it hasn't, so I wondered if anyone has any other ideas. My 1.8T has a Jabba remap and I have also had the 17505 fault since it was done ob

ver 3 years ago. Tried most of the easier fixes for this without success either but don't think they are related.

17544 is Long Term Fuel Trim Add.Fuel,Bank1 System too Lean

it doesnt actuall mention the co sensor so i would say thats a mapping problem or fuel pressure to low for a generic map. possible dirty injectors partially blocked up maybe.

Have you checked for boost leaks? I had a similar error when my aftermarket turbo intake had come off at the turbo end.

17544 is Long Term Fuel Trim Add.Fuel,Bank1 System too Lean

it doesnt actuall mention the co sensor so i would say thats a mapping problem or fuel pressure to low for a generic map. possible dirty injectors partially blocked up maybe.

What do you mean by a co-sensor? Could it still be a mapping problem even though this fault didn't appear until about 2.5 years after the map. It's a custom map (Jabbasport rolling road) rather than generic.

All the hoses have been checked over and I've replaced a couple of pappy looking ones but there is nothing obvious.