My first post and I'm unable to see any similar existing ones so please be gentle.
I have two problems as per title.
I've had the car 3 months now and am working through the few problems with it, I've already fixed the speedo and fuel guage by cleaning and reseating the wiring to both the diff and fuel tank sensors. The obc is under-reading both fuel consumption and speed although the gauges are accurate.
I completed a hundred mile gentle drive along the M4 this morning and never showed more than 20.2 mpg. The speed never showed more than 27mph. Do the sensors I have already cleaned send the signals to the obc or only to the gauges. If there are other sensors for this does anyone know where they are?
The other problem is the check control unit,with no lighting on there is no problem with this as you'd expect, but when the lights are on and the brakes are used it reports a fault and almost always shows faults for dipped beam and license plate lights as well during the journey. I've already tried a different ccu unit and replacing bulbs with new but to no effect,all earths on the lights themselves have been cleaned too. Is there usually a particular starting point for fault finding this?
Any ideas would be appreciated.Thanks.