My wife's car is 2004 estate the fuel gauge has been act strange in the last five day, the car have done 167,056 miles on the clock and the engine is 1.9tdi 115. When she drove sometimes it go up half needle then drop flat and the light of low fuel warning coming on. It keep repeat for sometime but most of time the needle is lay at the red mark, the car been to my local Fuel & Injection Bosch electrical specialist because it will be cheaper than VW Dealer, the Skoda and Seat dealer too far away where we  live. They plug in VAC what they called is diagnostic tool, it did not appear any error codes! but it reading the litre of fuel in tank is 42 litres it should be above half needle but the car is not. He said is either cluster fuel gauge or the sending unit level are likely to be a faulty. He said cost of carry out job it will be least at £400 include VAT to see the cluster first then the fuel sending unit.

 

I see on Youtube is easy DIY for myself to save money, is certainly do with fuel sending unit in the tank or a gauge failure?

 

 

Edited 20 March, 20197 yr by Theflyingpostman

I had a similar fault with my old Mk4 Golf many years ago and it was a faulty sender unit in the tank. Once replaced the fault was cured. Hope this helps

@Theflyingpostman - If this car has a trip computer, does the "available range" mode on it mirror the behaviour of the gauge or, if you zero the trip distance when filing right up, move such that range + trip stays about equal to the available range 5 miles (say 8km) after the fill?

She said when she reset the trip computer, the range after fill the top, drove after 20miles it said zero numbers on range trip computer it thinks the fuel is empty but it actually is full. Dilksie said the sending unit is a faulty.

Edited 22 March, 20197 yr by Theflyingpostman

@Theflyingpostman - That pretty much confirms that the sender is faulty (which is why I asked about the trip range; if it had been the gauge the computer would probably have worked correctly). As for the lack of fault codes, what would you test for?

Tomorrow what I am going to do is test the Ohms which I have Multimeter plug in the sending level connector when is full it should be round 40-60ohms and low round 250-180ohms that is what youtube show, the car fuel is probably low by now I am try out at the petrol station to fill it up and watch the multimeter numbers to see if is function.

@Theflyingpostman - I'm not saying this is the case here, but I've heard of level floats developing holes before.

Its all of 2 minutes to remove the sender and to bench test it, the fault will probably reveal itself visually.

 

On mine I had to put a tweak on the wiper of the potentiometer to ensure it remained in contact, it worked but failed again within 18 months.