I had a goofy fuel tank gauge; it ended up being the fuel level sending unit, on the original VW oem VDO pumps, it is a separate removable part screwed into the body of the fuel pump.
This would require removal of the fuel pump; if the pump is old you might consider, rolling the cost of the sending unit, into the purchase of a new pump, a oem Bosch fuel pump is revised with a integrated fuel level sending unit and includes a new rubber tank seal.
Checking the cost effectiveness of the sending unit and another pump; may help your repair direction, parts purchase. Looking on FCPEuro's website; the fuel level sending unit, by itself is in the $63 (Bosch) to $155 (genuine vw), price range, so a new pump, maybe a way to go with a whole Bosch fuel pump, being in the $150 range?
For diagnosing the problem; I ran a scan with VCDS by Ross Tech and there was a factory VW trouble code, for the fuel level sending unit being defective. Also, with a scanner like that; you can do a output test on the speedo cluster and confirm, the gauge is working as it should.
Once, the fuel pump is removed; you can inspect the level sending unit and follow the resistance testing procedure, outlined in the service manual.
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This would require removal of the fuel pump; if the pump is old you might consider, rolling the cost of the sending unit, into the purchase of a new pump, a oem Bosch fuel pump is revised with a integrated fuel level sending unit and includes a new rubber tank seal.
Checking the cost effectiveness of the sending unit and another pump; may help your repair direction, parts purchase. Looking on FCPEuro's website; the fuel level sending unit, by itself is in the $63 (Bosch) to $155 (genuine vw), price range, so a new pump, maybe a way to go with a whole Bosch fuel pump, being in the $150 range?
For diagnosing the problem; I ran a scan with VCDS by Ross Tech and there was a factory VW trouble code, for the fuel level sending unit being defective. Also, with a scanner like that; you can do a output test on the speedo cluster and confirm, the gauge is working as it should.
Once, the fuel pump is removed; you can inspect the level sending unit and follow the resistance testing procedure, outlined in the service manual.
Sent from my iPhone using Tapatalk