Audi speedometer under reads by 25mph so failed MOT. (1 Viewer)

[Spriddler]

I know it's O/T but there are some knowledgeable folk on Fun so worth asking.

2004 Audi TT 3.2L Roadster.
It's my son's treasured car and has just failed the MOT as the speedo needle at rest is below the 0 mph position and therefore reads a constant 25mph slower than the road speed. It's as though the needle has slipped round on its spindle. All other dash dials and lights are working fine.
The local MOT garage can't (doesn't want to) deal with it and the Audi main dealer said they would have to sub it out to a specialist but wouldn't suggest who it was.
I've Googled and YouTubed the symptoms til I'm blue in the face so have a fair idea of the workings and potential causes but have decided we need to take it to a specialist since although I'm experienced in vehicle mechanical work and straightforward electrics I've seen on YouTube that the stuff behind the dash cluster and dials is all delicate pcbs and chips. I'm near Brighton and have found on Google a specialist in dashboard cluster repairs ('from £150') near Portsmouth, about 60 miles from me but can anyone suggest someone nearer?

 

[BouncyBoatFolk]

??? I didn't think the speedo was a failure item. Speed can read, ( accuratly) of a GPS!!.
Mike.

 

[Lenny HB]

found on Google a specialist in dashboard cluster repairs ('from £150') near Portsmouth, about 60 miles from me

I take that was Caratronics at Waterlooville, less than 50 miles from you and they are excellant all the traders use them.

 

[Spriddler]

??? I didn't think the speedo was a failure item. Speed can read, ( accuratly) of a GPS!!.
Mike.

I looked all that up at length in the MOT Tester's Manual and it is (now) a fail as unknown or incorrect speed indication can be dangerous.
GPS isn't acceptable as an alternative because it won't read if the signal is poor or lost, e.g. in the Dartford Tunnel. The other thing was that GPS is100% accurate and by law a speedo must over-read (by up to 10%) and never less than the road speed.

 

[Spriddler]

I take that was Caratronics at Waterlooville, less than 50 miles from you and they are excellant all the traders use them.

Great. Thanks Lenny, that's good to know. Yes Cartronix. <50 miles is fine, as was 60 but happy to go almost any distance if the firm is known. Websites can say anything so I'm always a bit circumspect having made disappointingly fruitless trips for other things to firms claiming to be experts when I knew more than they did.
They say they'll remove, repair and refit which is ideal, so I'll give them a call and take a chance driving it down there.

https://cartronix.co.uk/product/audi-tt-speedometer-repair-dashboard-instrument-cluster-processor-repair-instrument-fault-repair/

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[Lenny HB]

Great. Thanks Lenny, that's good to know. Yes Cartronix. <50 miles is fine, as was 60 but happy to go almost any distance if the firm is known. Websites can say anything so I'm always a bit circumspect having made disappointingly fruitless trips for other things to firms claiming to be experts when I knew more than they did.
They say they'll remove, repair and refit which is ideal, so I'll give them a call and take a chance driving it down there.

https://cartronix.co.uk/product/audi-tt-speedometer-repair-dashboard-instrument-cluster-processor-repair-instrument-fault-repair/

I used them for the dash light problem on my last van.

 

[pappajohn]

Probably nothing more than the stop pin has come out of its hole on the dial face and the Speedo is as accurate as it ever was.
If the needle was meant to rest at zero mph they wouldn't need to fit a stop pin.

 

[Steve N Tracy]

I have done a few speedos face changes, if you can get to get the old needle off a couple of teaspoons can make a usefull tool.
As you will not have the use of a rolling road you will have to use a sat nav to show the speed, find a large car park or very quite straight road and take the vehicle upto 20 mph and put the needle back on the spindle just over the 20 mph mark, UK speedo are aloud to read over by 10% and most do.

 

[Spriddler]

Probably nothing more than the stop pin has come out of its hole on the dial face and the Speedo is as accurate as it ever was.
If the needle was meant to rest at zero mph they wouldn't need to fit a stop pin.

Yes, I've been thinking it's something like that but although I've seen on Youtube how to get the dash assembly out and open up and dissect the instruments the car's in beautiful condition and I don't want to risk causing cosmetic blemishes to the dash............and some jobs have always looked simpler/easier on YouTube than when I've had a go.

 

[WESTY66]

I used them for the dash light problem on my last van.

Did you get the airbag light sorted, and the MOT?

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[Lenny HB]

Did you get the airbag light sorted, and the MOT?

Keep up boy, yes £642 lighter.

 

[Ingwe]

I also used Cartonix. Sent them the van’s instrument cluster on the Monday and received the repaired instrument cluster on Friday £150 plus postage but against a dealer quote of nearly £400.

 

[acropolis22]

I looked all that up at length in the MOT Tester's Manual and it is (now) a fail as unknown or incorrect speed indication can be dangerous.
GPS isn't acceptable as an alternative because it won't read if the signal is poor or lost, e.g. in the Dartford Tunnel. The other thing was that GPS is100% accurate and by law a speedo must over-read (by up to 10%) and never less than the road speed.

To be pedantic, GPS isn't 100% accurate because when you are decelerating or accelerating there's a bit of a lag in the speed reading. At least that's how it seems to me. Presumably because it has to calculate in arrears, if you see what I mean.

 

[Steve and Pam]

To be pedantic, GPS isn't 100% accurate because when you are decelerating or accelerating there's a bit of a lag in the speed reading. At least that's how it seems to me. Presumably because it has to calculate in arrears, if you see what I mean.

Could he fit something like this.

Car HUD Head Up HD Display Over Speed Warning OBD2 Digital Speedometer Projector | eBay

Pickup Trucks and Modified ECU vehicles are not suitable for this HUD. 1 x mate Car HUD. The OBD2 mode are not compatible with following cars Display way virtual image reflection. - France cars manufactured by FAT,DS,PEUGEOT,Citroen,Renault,Simka, Amirka.

www.ebay.co.uk

 

[Spriddler]

I have done a few speedos face changes, if you can get to get the old needle off a couple of teaspoons can make a usefull tool.

Ta, but although I've restored a few Smiths chronometric (i.e. clockwork) speedos for my classic Brit motorbikes I'm happy to pay someone else these days.
I did a 5yr indentured apprenticeship back in the 60's at a R/R, Bentley and Jag main dealer and have restored no end of 'classic' cars but I'm now in the fortunate position that I can value my patience and blood pressure higher than money. .

I also built my own kit car and two of the restored MGB GT's I gave to my sons. My, how we posed in them!

I declined my elder son's request to 'help' him (aka provide the dosh as well as the labour) to convert his Beetle into a beach buggy. He said it was simply a case of unbolting one body and bolting on the new as per the magazine article that he stuck under my nose with a smiley Adonis type building it in a huge garage with a post lift and wearing white sneakers, fawn Chinos and an immaculate white polo shirt. I told him that real life is rarely like that and pointed that in the magazine photos Even the spanners are smiling! which has now become our family standard dismissive comment whenever someone gets a mad idea.

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[Spriddler]

To be pedantic, GPS isn't 100% accurate because when you are decelerating or accelerating there's a bit of a lag in the speed reading. At least that's how it seems to me. Presumably because it has to calculate in arrears, if you see what I mean.

Yes, I realise that detail but without going into all the variables my prime point was that a GPS isn't an acceptable speed indicator for the purpose of the MOT.

Could he fit something like this.

Car HUD Head Up HD Display Over Speed Warning OBD2 Digital Speedometer Projector | eBay

Pickup Trucks and Modified ECU vehicles are not suitable for this HUD. 1 x mate Car HUD. The OBD2 mode are not compatible with following cars Display way virtual image reflection. - France cars manufactured by FAT,DS,PEUGEOT,Citroen,Renault,Simka, Amirka.

www.ebay.co.uk

Thanks. Maybe he could, but we want to keep it original and correct. I know from my past (lethargic) experiences that fixing stuff with even supposedly temporary 'work-arounds' is the thin end of the wedge, as before one realises it the vehicle has a variety of idiosyncrasies and non-standard anomalies that rarely get corrected.

 

[Coastal Cruiser.]

£642 lighter.

 

[tacr2man]

there's quite a few TT speedo assy on ebay

 

[rod_vw]

Get someone with VCDS to scan the car and also check that the sensor is reporting the correct speed before you blame the dash insert out of hand.
There must be AUDI forums which can provide good advice and reliable solutions. Try https://www.ttforum.co.uk/.

 

[MattR]

Tbf, I didn't think that Audis had speedos... that's why so many Audi drivers seem to drive up the ar$es of the cars in front so they can read their speedometers.

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[Just smiffy]

As above cartronix….

Speedo Repair | Instrument Cluster Repair | Dashpod Repair | Cartronix

Faulty instrument cluster? Speedo repair needed? We will help, we are dashboard repair specialists and repair all instrument panels. Call for a quote!

cartronix.co.uk

 

[Spriddler]

there's quite a few TT speedo assy on ebay

I looked at them. New (?) ones at around £150 plus cheaper used ones but I'm not willing to risk a s/h dash cluster and I'm looking for the most convenient and reliable solution rather than the cheapest.

Get someone with VCDS to scan the car and also check that the sensor is reporting the correct speed before you blame the dash insert out of hand.

I'm going to do that but the independent garage that my family and I have used for 25yrs weren't able to fit it in to the workshop at 5.30 after the MOT and the guy in the MOT bay doesn't do anything else but MOT's.

There must be AUDI forums which can provide good advice and reliable solutions. Try https://www.ttforum.co.uk/.

I've looked on several Audi/TT forums and on YouTube but none cover the same fault but show other faulty gauges or a speedo that doesn't work at all.

 

[Rama]

I had the exact same problem with a VW T4 speedometer & it turned out to be an easy fix. I think it's possible that your Audi speedometer might be the same or at least similar as it's VAG.

I've lost the post that told me what to do, so this is from memory:

Remove the speedometer unit and take off the front cover so you can access the needle.

Using your finger gently rotate the needle all the way round clockwise, it will move freely then meet some resistance which you can gently push against and it will click further round.

When you release the needle it will return, but not all the way to zero, stopping on something like 30mph.

Now gently push the needle back down towards zero, again you'll feel some resistance, a sort of ratchet feeling. Stop when you get to zero & job is done. If you find you've gone a bit too far repeat the process.

It worked for my T4, hopefully will work for you as well and save you the cost of a repair.

 

[Spriddler]

I had the exact same problem with a VW T4 speedometer & it turned out to be an easy fix. I think it's possible that your Audi speedometer might be the same or at least similar as it's VAG.

I've lost the post that told me what to do, so this is from memory:

Remove the speedometer unit and take off the front cover so you can access the needle.

Using your finger gently rotate the needle all the way round clockwise, it will move freely then meet some resistance which you can gently push against and it will click further round.

When you release the needle it will return, but not all the way to zero, stopping on something like 30mph.

Now gently push the needle back down towards zero, again you'll feel some resistance, a sort of ratchet feeling. Stop when you get to zero & job is done. If you find you've gone a bit too far repeat the process.

It worked for my T4, hopefully will work for you as well and save you the cost of a repair.

Thanks. I did consider that as it seems, as I said, that the needle has 'slipped' round on its spindle but I'm not keen to faff about removing the dash cluster and dismantling it even though from youTube videos it seems fairly straightforward. However, I'm still in two minds about trying that and will mention the possibility when I speak to Cartronix tomorrow.

 

[Spriddler]

To conclude.......
Took the car to Cartronix near Portsmouth today (100 mile round trip) and they removed the dashboard, refurbished the speedo and refitted the dash in an hour and a half for the quoted £190. Stopped off at my local garage on the way home and they checked the speedo and issued an MOT Pass. Great result and thanks Lenny HB for your confirmation of Cartronix competence.

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[pappajohn]

they removed the dashboard, refurbished the speedo and refitted the dash in an hour and a half for the quoted £190

£125 per hour.......they love folks like you.

Just out of interest, how did the tester know it was 25mph out.
They don't physically test the speedo.

 

[Spriddler]

£125 per hour.......they love folks like you.

I'm not naive when it comes to auto repairs and restorations (see my post #15 above). I used to be happy to apply my time, energy and patience grovelling about and contorting myself under and inside vehicles building and repairing them, partly out of economic necessity. I've been there and done that professionally and as a hobby for 60 years (got the spanner rashes to prove it). I'm 77 now and think I deserve a break so happy and can afford to let someone else do it.
I still restore and repair classic Brit motorbikes with them up on a bike lift at waist height.

Just out of interest, how did the tester know it was 25mph out.
They don't physically test the speedo.

Err, well the speedo needle at rest was about 3/8" below the 0mph mark and didn't align with it until driving at about 25mph (my guess). The MOT tester noticed it when doing the brake test on the rolling road.
He retested it when I got back from the Portsmouth repairer today by driving it 300yds around the block. I've known the garage owner for about 45 years and used to prepare his racing Mini and attend meetings with him until I started becoming a stranger to my disgruntled wife and kids.

I hadn't realised that the speedo was now part of the test regime as a major defect.
It says 'inoperative' although it indicated all the right numbers........ but not necessarily at the right time.

 

[pappajohn]

He retested it when I got back from the Portsmouth repairer today by driving it 300yds around the block.

Then that cancels the MOT.
The tester has no authority to drive the car during the test and whatever the result was it can't be applied to the test.

 

[Lenny HB]

Then that cancels the MOT.
The tester has no authority to drive the car during the test and whatever the result was it can't be applied to the test.

So if it was your car John would you reject the MOT?

I thought the brake test was driving the car around the block with an inertia gauge in the passenger footwell.

 

[pappajohn]

So if it was your car John would you reject the MOT?

I thought the brake test was driving the car around the block with an inertia gauge in the passenger footwell.

Jeez Lenny, when did you last have an MOT?

I would want to know what evidence the tester had the Speedo was wrong.....without driving it he wouldn't know.
To my mind it should be an advisory.

Mine failed on Wednesday on both rear brakes excessively binding and an advisory for n/s front binding slightly.
Visible evidence on the roller brake test.
That couldn't be disputed as it was recorded by the machine.

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