Fuel Gauge Seems To Be Frozen

[Deep Blue]

2009 Passat CC 2.0L TDI, 6spd DSG
CBBB engine

Have been okay with exhaust gas sensor so leaving that one for now. Went to start car today, almost certain fuel tank (diesel) is empty! Turns out my wife had been driving it and she mentioned that it didn't seem to use any fuel!!! Anyway, tank shows 40% full - permanently! About a month ago, the MFD said 140km before refuel (it had always been super accurate) - anyway, car ran out of fuel. Didn't think about it until yesterday - seems gauge permanently says 40%.

Is it worth me pulling the fuel pump out to have a look (sender unit)? I read the fuel gauge issue is not uncommon?

[sn809]

Yeah definitely. If you have the time you should clean up the tank as well. Ensure you get microfibre cloth, doesn't leave residue behind. You may want to just get a reconditioned/used unit.
Also remember the pump takes a lot out of the battery so if you need to prime (key method or VCDS) try and keep the battery on charger/keep system on supply mode if your battery charger permits.
Plenty of good videos around, use a blunt object with hammer to remove the metal plate not a flat screw driver, just be wary that as soon as the metal plate will come off it will pop up. Also take a photo for reference so you know which bit goes where.

Mine is a B6 BMR

[Deep Blue]

Checked fuel gauge and low fuel warning light using diagnostic tool - all good. For good measure checked for engine codes - all good.
When I put key fob in the ignition and moved to position 2 the fuel gauge went straight to 40% again - the figure it's been on for some time!

Leads me to believe the tank is empty and fuel gauge erroneously shows 40% - reason engine wouldn't turn over. So, suspecting sender unit/float issue - maybe stuck? [This happened before a couple of weeks ago and I had to get a jerry can to refill and then start the engine.]

Here is underneath back seat behind RHD driver's seat (undo electrical connector for one seat heating element and lift off):




After the snug fit rubber cover is pried off to reveal the top of the pump:



Looks simple enough, tried removing the electrical connector, but it won't budge at all! Got dark, so will vacuum all the dirt off tomorrow and have a go at removing the connector again - lift red button up and pull plug off (may spray with some penetrant)? Don't want to break the connector! Fuel supply and return line removal should be fine. Noted pump is a Siemens (Siemens VDO also OEM pump manufacturer for my Land Rover in-tank pump).

Will be interesting to see if there is something obviously amiss with the sender unit/float?

[Deep Blue]

Funny thing, had a look at YouTube and seen this: YouTube

Can't work this one out (YouTube video) - he seems to fix his fuel gauge error by just removing the in-tank pump and just putting it back in again with some additive???

[JustCruisn]

I watched that and in the end his gauge is still stuffed.
18min of how to not fix the fuel gauge.
At least you know how to do it, just ensure you swap it out for one that works.

[Deep Blue]

Don't think you can replace sender unit? Assuming if sender unit isn't working (but pump is okay) then you still have to buy a new pump (includes sender unit)? Is that right?

Okay, Part Number is 3C0919050 Q. Siemens VDO pump made in Germany.

Waiting on reply from dealer re availability and price. Tried eBay, nothing available locally as far as I can see. Any thoughts on where I can get one for a good price if I decide to replace the existing unit?

[Deep Blue]

Apparently VW dealer does sell sender unit for the pump (available ex-Germany on couple of weeks delivery) for $294.

Pump (including sender unit) from dealer is $683.

Will pull pump out (just struggling to disconnect the stubborn electrical connector - will try pushing the red tab down and pulling up, rather than red tab up) and check sender unit variable resistor for damage/dirt and then check smoothness of resonse with multimeter resistance test.

[Lucas_R]

Get it from the UK. Cheaper than local and it will be here within a week. Pierburg In Tank Lift Pump / Fuel Delivery Unit - VW Passat / Passat CC - 3C0 919 050

[JustCruisn]

So you can buy the whole thing from Europe for less then the dealer wants for just the sender.
Now you have part numbers, go check it on ebay. Or call a local wrecking yard, a used one might be worth it given how easy it is to replace.

Used $150 delivered from Dandenong
from a golf I assume they are the same.
GENUINE 2008 VW GOLF V EDITION 1.9L 04~09 Diesel Fuel PUMP 1K0 919 050 | eBay

New UK $170
VW Passat B6, CC 1.9 2.0 TDi In Tank Fuel Pump + Fuel Sender Unit 2005-2012 | eBay

New UK $280
FUEL SUPPLY MODULE MAGNETI MARELLI OEM 3C0919050G 313011313045 HEAVY DUTY | eBay

[Deep Blue]

Thanks JustCruisn - good options there, appreciate it. Always wise to look around - amazed at the price variations in most cases. My part number is 3C0 919 050. The first link for part 1K0 919 050 looks a bit different to mine as far as the fuel connection points go?

Okay, not sure re the electrical connector. The small red tab can shown in the picture can be moved up (away from the top of the pump) or down. It doesn't seem to have any resistance (as if it isn't sprung). Just can't pull the plug up! Assuming if the red tab is pushed down then the connector should be released and should be able to be pulled up and off???

Will try again, don't want to damage the connector, but have never encountered such a stubborn plug!

[Lucas_R]

Okay, not sure re the electrical connector. The small red tab can shown in the picture can be moved up (away from the top of the pump) or down. It doesn't seem to have any resistance (as if it isn't sprung). Just can't pull the plug up! Assuming if the red tab is pushed down then the connector should be released and should be able to be pulled up and off???

Will try again, don't want to damage the connector, but have never encountered such a stubborn plug!

Sometimes those red connectors can be a real pain to figure out. Try lifting it up away form the plug and then you might see a tab on the black part of the plug that will need to be depressed in order to remove the plug.