non-functioning speedo needle!

C

claracluck

Member
I have another minor but irritating problem with my 2001 1.4TDi,the speedo needle appears to have developed a mind of its own and doesnt always register what my current speed is.I can be travelling at 70mph and its registering 0mph! Slightly disconcerting-especially for my husband who drove her recently! I have been using my rev gauge to give me an indication of my speed.It will also sometimes wave around quite madly and usually then settle down and record the right speed,particularly if I ease my foot off the accelorator.
I recently wrote in about my power steering warning light coming on and had an independant but Audi trained guy out to check her out,when he plugged all the gizmos in he couldnt find any fault registering at all!
Any suggestions as to what could be causing this problem,is it somehow connected to the warning light problem and again is it likely to be easy to fix?
 
It could be linked to thepower steering light, but I think that this is more likely to be a dodgy speed sender that is on its way out, hence the somewhat intermittant fault.

However, there is a remote possiblity of the dash panel being faulty, especially if you are getting power steering warnings without actual faults.

Cheers,

Mike
 
It's a sensor that sends info on how fast the engine is turning to the engine ECU. Thinking about it now, it could even be a faulty gearbox speed sender! Chances are a fault code will be stored on this one, especially if you can catch it when it's actually happening.

Cheers,

Mike
 
Thanks again,is it an expensive problem to fix? I've spent nearly £1500 over the last 6 months sorting various bits n bobs out I dont want to be starting with yet more expense!!
 
It's probably not expensive (for instance, the gearbox speed sender is just over £50), but it depends on who does the work as to how much the total will be.

For instance, Audi main dealers typically charge £100 per hour labour, so for a 90 minute job, you'd be looking at £200 or so.

If the clocks are faulty, then you're looking at the best part of £500.

Cheers,

Mike
 
Beaaring in mind the previous no-show of any faults (when they were present on the dash - the power steering), I'd be wary of the same diagnostics chap, especially if there are VCDS-equipped members in your area, most of whom will charge no more than £20 for a scan.

It's a pity you're down there, as opposed to up here, otherwise I could sort you out!

Cheers,

Mike
 
Hi Guys,havent been online for a couple of days so only just got replies! can you recommend anyone down here-as you so quaintly put it! I'm actually a northern girl but ended up down in the south somehow or another!!
 
Identical Problem

Hi everyone,

I just logged on to search the forums for speedo faults and found this thread. My 51 plate 1.4TDI has exactly the same problem. It started 2 days ago at the end of my journey home. The speedo started jumping around, reading both above and below the correct speed. On my way to work the next day it was doing the same thing, I also found it was engine load related. On full throttle it was really bad, but as soon as I backed off to cruise at a constant speed it worked perfectly.

On the way home from work that day about half way through my 17 mile journey I got a power steering warning light, which has never happened before. At the same time the steering got lighter, as if the speed sensitive part of the power steering stopped working. It was a noticeable change, my journey is down a twisty country lane and it changed the feel of the car dramatically.

I also assumed it was a sensor issue, but I wasn't sure if the speedo used the wheel speed sensors or another sensor in the gearbox. From your replies skipton, it seems there is a gearbox sensor, which is probably at fault.

Where is the gearbox sensor fitted? it is accessable from the outside. I am an automotive engineer by trade, but often get my hands dirty and do my own servicing and repairs on my cars.

Best regards

Andrew
 
Hi Andrew,
How strange that your car started doing what mine is doing.Mine is also a 51 plate and I had also had my power steering warning light come on for no reason-but no steering lightness though.One of the seasoned contributors contacted me directly and he has the equipment to try and find out what is causing this fault,if you want the details send me a message.I havent had time to get in touch with him yet but intend to,perhaps he could sort both of us out at the same time!
Best wishes,Claire
 
Locate the gearbox speed sender and trace back the wiring. Check near chassis member and around pipes and so on as I have had wires rubbing through causing erratic speedos.

This may be linked to your PAS as it may be sprred sensitive and if its not getting and increased speed signal, the pump will work harder resulting in lighter steering.

Pic attached
 
Hi Fisheggs,

Thanks for the info. I am knee deep in boxes at the moment preparing for a house move, so I havn't had a chance to have a look yet.

I also assumed the electrohydraulic power steering pump was going into a failsafe mode as you say, generating extra pressure rather than none at all. this fault has happened 2 more times since my first post, but is always cleared by a key off and on again.

Cheers

Andrew
 
Problem Solved

Hi Everyone,

I had a bit of spare time this afternoon so i had a look at my car. I found and fixed the problem. One of the 3 wires that connects to the gearbox speed sensor was broken. It had broken only 30mm from the connector and it was caused by a bad loom design in my opinion. This part of the loom goes to 2 sensors, the gearbox speed and the engine crank speed sensors. The point at which the gearbox speed sensor connection breaks out of the loom is in the wrong place, it is too far along, causing the the wires to double back on themselves. The loom has a stiff reinforcing sleeve at the breakout point to stop the loom covering from spliting, but because the wires were pulled tight, doubled back arround this stiff edge it cuased the wire to fatigue and break right through.

I had to disconnect the crank sensor in order to extract that part of the loom to get access to fix the brokem wire. While i was soldering in a new section of wire, i cut back the outer loom cover by 50mm so the gearbox speed connection branches out sooner. It now sits much better and hopefully shouldn't cause a problem again.

A lesson to be learned though. A bit of preventative maintanance could prevent a failure in the future.

Best regards and thank you all for your help and suggestions

Andrew
 
A problem has just arose on my 01 1.4 se. The speedo has stopped working. It does work intermittently and the petrol gauge is also jumping about. Would be grateful for any thoughts what the issue may be prior to contacting garage. Car is running fine, so suspect it may be a wiring issue?
 
djn i can't offer a fix. But the best way to find out whats going on is to get a scan done with vcds.

I am only down the road in Huntingdon so if you want one doing then give me a shout.

Cheers

David
 
I will pop into my local independent vw/Audi specialist this week, and they will run diagnostic free (really good garage, looked after my last a2). However, really appreciate the kind offer.
 
fisheggs said:
Locate the gearbox speed sender and trace back the wiring. Check near chassis member and around pipes and so on as I have had wires rubbing through causing erratic speedos.

This may be linked to your PAS as it may be sprred sensitive and if its not getting and increased speed signal, the pump will work harder resulting in lighter steering.

Pic attached
Click to expand...

Where abouts in the engine bay is the sender... Mine bounces every now and again, will check the wiring first before replacing things...
 
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