QuestionHello all, I have just purchased my first Audi A4, I seem to have a fault with the electrics and I have no idea what is wrong can you help?
This fault is intermittent and clears after approx 5 - 10 min.
When driving along I receive a message on the dashboard saying fuel is nearly empty when the car is full, the fuel gauge goes to empty and the outside temperature reading display drops to -40! Also the engine management light comes on. And also a symbol which says that the washer bottle is nearly empty as well.
Sometimes when this happens the fuel gauge stays fine but the engine temperature gauge falls to 0. The car runs fine with these lights on and then after approx 5-10 min the fault disappears.
The car can be running fine then the fuel guage displays differnet readings along with the outside temprature guage.
I have had the car to a local garage who has had it on the computer and there is no engine trouble it seems to point to the the sensors and electronics, The garage have sent the instrument cluster to BAA REMAN who run full diagnostics on the instrument cluster and no fault was found so I decided to start with the cheapest sensor and replaced the outside temp sensor which made no difference.
Their is no water damage in the passengers footwell and the fault sometimes does not accur again for days its totally ramdom.
Does any one have any idea what can cause all these faults to happen at once.
Just Got the Readings from my car if this helps?
01039 Dash Coolant Temp
0771 Fuel Level
00779 Ambient Temp
Open Circuit / Short with power intermitant
00576 Terminal 15 (not plausable signal)
Cheers
Tom
AnswerYou probably found the reason that the car was traded in... Anyway I think the problem may be a multitude of things, or a single ground connection which is losing contact. First thing to do is identify the major gound points, and ensure that these are clean and tight. These faults are the hardest to find, and I have made monitoring tools before to help find the cause. It depends on how handy you are with LED's and a soldering iron, but you can attach a monitoring circuit to both the sensor-side of the fuel gauge (+ve) and to the negative side through LED's and then have a box with the two LED's on the dash. Once the fault occurs, one of the LED's will go out, and this will give you the identification if it is a ground problem or a short in the positive line. As soon as you know that, the troubleshooting process is halved... Let me know what you find, Jan
P.S. Dealers do not do this type of troubleshooting typically, they typically start throwing labor costs and parts at these problems; which costs you a lot of money but can take a long time before the problem actually gets found. Can you go back to where you bought it?
