1. Home
  2. Car Maintenance
  3. VW Polo Petrol Gauge Not Working

VW Polo Petrol Gauge Not Working

Hi

My daughters 10year old Polo, "P" reg Petrol Indicator stopped reading.

Things I've checked:

At sender unit, connector has 4 wires, non show more than 4.63 volts, yet two are for petrol pump and that is working fine.

Fuses are all OK.

Checked wiring under carpet, the v4.63 volts is present all along, nothing appears to be leaking to earth.

The Haynes manual is not clear as to where the supplies originate, i.e. they just come out of boxes with multiple wires going in and out.

Anyone know what voltages should be present?

Any suggestions as to the way forward.

Cheers

I know a garage would probably fix this but with a car this age, well I'm sure know where I'm coming from.

Reply to
Driver
Loading thread data ...

With the greatest of respect, either your meter is broken, or you are not using it correctly.

The fuel pump supply voltage must be at, or *very* near, the battery voltage if the pump is working. I'm reasonably confident VW would not have designed a pump for 4.63 volts...

The fuel gauge sender unit is usually a variable resistance. Usual DIY test is to short it, then open circuit it to see if the gauge moves from full to empty. DO NOT try this until you are absolutely sure you can correctly identify the wiring.

Chris

Reply to
Chris Whelan

You should be able to identify the wiring from the colours listed in the Haynes BoL.

Reply to
Chris Bartram

the pump will not show correct voltage unless the engine is running. red with a yellow is power, brown is earth

one of the other two will put the low fuel light on or be earth, the other the gauge

ignore the two for the pump, earth each of the others to find the one which makes the gauge work. repair or replace the sender unit (most likely)

Reply to
MrCheerful

Thanks for your suggestions

Reply to
Driver

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.