1.8t AUQ Speedo/Fuel Gauge Issue.

[SlashProm]

Having a problem with my speedo not working as well as the odometer and as a result the fuel gauge is not being told the car is in motion so I'm also getting the annoying beep.

My problem is that there are so many different types of speed sensor it gets a little confusing.

Gearbox is 02M - This is the speed sensor(g22) for my vehicle which I have replaced already. 1J0919149A

Being a hall effect sensor I expected it to pick up off a magnetic ring on the output shaft inside the diff casing but the part I'm looking at seems to be for a different type again, same sensor but slightly different shape and positioning. 012409182C

I have a diagram here of my gearbox from TPS and there is nothing here that shows a drive gear of any description, the closest thing to it is the taper roller bearing.

https://nemigaparts.com/cat_spares/etka/seat/le/205/409300/.

Anyway just looking for some clarification, does my g22 have a pickup ring that could be broken or is my problem likely to be with the wiring/instrument cluster?

 

[mty12345]

Hi mate, there is an increasingly common fault with the instrument cluster....it causes any/all of the following:
1. The back lights to flicker, and to stay on without the key in the ignition.
2. Dim warning lights that shouldn't be there. (there is no fault, just the light)
3. The revs/speedo/fuel/temp gauges to stutter, freeze or stop working.
4. The immobiliser to stop talking to the ECU, and then the car won't start! (Although once it has started,then for safety reasons it will continue to run no matter what the immo/cluster does)

There are companies that will repair the cluster for £150 ish if you send it off to them...You will not be able to start the car whiie it is away!
Another option is to buy a new one, £401 from SEAT!! plus you will need it coded to your car.
The third option is a secondhand one, (although it may well have the same fault) you will need the PIN from the old car, the PIN from your car and someone to code it for you. All in all a bit of a nightmare.

I have had this issue and it's caused by where the 2 connectors on the back of the cluster join the circuit board. Unfortunately there are about 40 pins on each socket, they are very close together , and they all need to be resoldered.

I also found this fault only occured in the winter, when the cluster gets cold at night. I believe the metal contracts with the cold, and that causes the bad solder joints to pull apart. If you remove the cluster, take it inside the house and warm it up, you will usually find that it will go back to working fine when you reinstall it.

 

[SlashProm]

Thank you for the prompt reply. I have an update if it helps.

I plugged the car in today and ran an output test on the instrument cluster. For the first time since owning the vehicle I saw the speedo move. Does this elimitate the instrument cluster because it's atleast able to move the clocks properly via an output test from the ecu. Or is it receiving an actuation from the CAN system? Basically i just want to know if passing the output test on the speedo means the instrument panel can be ruled out as the fault.

 

[SlashProm]

Update*

Plugged in to Delphi and ran some data. Not getting a speed signal input to the ECU. looks like it is gearbox side. Whatever the G22 picks up off. so into the gearbox I go to find out what this ring looks like. If it's the same as the other type I'm not going to be impressed lol

 

[mty12345]

Yeah if it's just those symptoms then i'd say its the input signal as you suspect. Can't help on which G22 it is though. I'll keep my fingers crossed for you.

 

[SlashProm]

I know which g22 I have as I've replaced it. The problem I'm having is that there doesn't seem to be a drive wheel for the sensor in my gearbox. Well at least that's what my Diagram shows. And I'd rather not strip the diff casing off the side of the box and shafts out and all that guff if I don't even know what I'm replacing.

 

[SlashProm]

Update: I think I found the problem but I'd just like a little confirmation before I start splicing.

There are 3 wires to the VSS(g22)
Black/White = 12v Live
Blue/White = 5v Signal/Reference for instrument cluster
Brown = Earth

Anyway. I probed the black/white live first with ignition on. it read 0.06-0.08v. I thought wow, it must be a broken live, but why is it not reading 0.00?
I then probed the blue/white signal wire and it read a steady 9.7v.

Correct me if I'm wrong but don't them 2 readings seem back to front to you? I would have thought 0.06-0.08 is the kind of reading the signal wire would show at idle at 0mph then climb towards 5v as I speed up?

Please confirm so I can cut these 2 wires and swap them over

PS: the signal wire is half the thickness of the live wire. So I'm thinking that's why it's only outputting 9.7v because it obviously steps down in wire thickness where it's been re wired wrong.

 

[mty12345]

Hi again mate. I have read those sort of voltages on ground wires before. I think it is down to multimeter inaccuracy and/or static or interference. i would take a reading that low to actually be zero myself.

You could be completely right on the wiring theory, especially as you have that pin out for the sensor, but i'd have expected the signal wire would more likely be at a constant voltage and that the signal would either be PWM, or more likely just the number of pulses per second. (I would of expected it to be 5 volts like you say though.... 9.8V is strange )This would also make sense with the fact that the pulse wire is thinner as it would hardly be carrying any current, whereas the thicker earth wire would be carrying the current needed to actually run the sensor.
I have also come across a fair few earths on these cars which are black with white stripe, and if someone had the knowledge to diagnose the VSS and attempt to replace it, then i would of imagined they would get the wiring right, if not the first time then definitely when it didn't work.

All that being said, those are just my thoughts on it buddy. I certainly wouldn't discount the possibility, but i'd definitely do some more research before attempting to swap them, you don't want to risk frying your ecu.


EDIT: here is a pin out for the green connector in the dashboard binnicle.
here is a bit more information:

32-pin connector, green

1 - Reading coil for electronic immobiliser.....17 - Reading coil for electronic immobiliser
2 - Warning lamp for main beam..................18 - Rear fog lamp warning light
3 - Warning lamp for dip beam.....................19 - Front fog lamp warning light
4 - Oil level gauge sender............................20 - Seat belt warning system warning lamp
5 - Speed signal, output...............................21 - Hand brake switch
6 - Speed signal, input.................................22 - Brake system warning lamp
7 - CAN L (motor).......................................23 - Oil pressure switch
8 - CAN H (motor)......................................24 - CAN Activation mode
9 - CAN L (comfort)....................................25 - CAN (motor), insulating shield
10 - CAN H (comfort)..................................26 - CAN (comfort), insulating shield
11 - Multi-functional indicator.......................27 - Multi-function indicator - Reset
12 - Multi-functional indicator.......................28 - Free
13 - Brake system fault indicator light...........29 - Warning lamp for tail lights
14 - Free....................................................30 - Windscreen washer fluid level sender
15 - Fuel level gauge sender........................31 - Exterior temperature sensor
16 - Coolant level warning sender................32 - Terminal 31

As you can see, the speedo signal comes in on pin 6. I would be much more inclined to suspect that was the cause, especially when coupled with the beeping you metioned in your first post. The solder joints on those connectors are crap and i found multiple dry joints when i opened one. I think the output test on VCDS may simply test the motor in the speedo gauge, rather than emulating an input signal from your sensor.

It may be worth asking on the VCDS forum as some of the people on there have excellent knowledge of all the electrical systems on these cars. https://forums.ross-tech.com/forum.php

 

[SlashProm]

Thanks but are you sure that's not the one for abs speed signal? according to my diagram, which has been right so far touch wood (eliminated up to the T14 connector for faults). It goes into T32 Blue on pin 10. (T32 - 32-pin connector, blue) Assuming T32/10 corresponds to pin 10 for the wire. Can you hook me a pin out of the blue connector as well please. Much appreciated.

 

[mty12345]

I can't find a pin out for that one sorry mate. It could well be the ABS signal, honestly not sure on that one.

 

[SlashProm]

*Fixed* Turned out to be a missing fuse. It took a few days and the right diagrams to lead me there, but in the event anyone has a similar problem to mine. Fuse 7 in fuse box 10a Mini Blade fuse. 4th row down 5th across. I knew instantly when I was reversing out of my parking spot. So happy I don't have to get in to the gearbox.

 

[mty12345]

Glad to hear you got it sorted mate I bet you had a few choice words for the previous owner who took the bloody thing out,lol..

 

[SlashProm]

A few is an understatement, when I got the car the strut wasn't fully seated into the hub on the drivers side, no speedo, black tape over a plastic water flange when ended up leading to a head skim I think the correct term is "monkey wrencher"