Speedo failure - M400

[shaun400se]

Morning folks....looking for some advice on above titled subject matter. Having suffered from speedo failure in my M12 GTO 3R during the latter stages of my ownership of same in mid 2006 (and getting a speeding tocket on the A74M when trying to coerce her down from Aberdeen to Derby to get it seen to) I now have a very similar (but not the same) problem with my 20 month old M400. Last night, having not used her for about 4 weeks, I took her out on what was a perfect Scottish spring evening, and within 4-5 miles noticed my speedo needle 'see sawing' up and down, between the 0mph marker up to anything that I was presumably 'cruising' at - without going into details of course, but you'll get my drift.

Now for sure when the needle was wedged firmly at 0mph there was NO mileage accumalating on my odometer, and after going through the normal checks to try and rectify i.e. ignition on and off, leaving car for an hour whilst I ate in a local restaurant, and checking fuses etc. I have not been able to rectify the problem.

Any ideas what has happened here, is ita common and recurring problem amongst other M owning PH'ers and is there any quick fix? Would be pleased to hear!

Rgds,
Shaun+

[AMG Merc]

Shaun, maybe you washed the car recently and water sprayed inside the front right wheel where the speedo sensor is located. Try drying it off with a hair-dryer.

Also, whilst you are speedo-less to avoid more speeding fines use your SatNav speed display.

[shaun400se]

AMG Merc said:

Shaun, maybe you washed the car recently and water sprayed inside the front right wheel where the speedo sensor is located. Try drying it off with a hair-dryer.

Also, whilst you are speedo-less to avoid more speeding fines use your SatNav speed display.

Thanks AMG Merc, I'll try that, so it's front offside wheel then?......any idea what it looks like i.e. is it obvious what it is? Will also take tip on Satnav speedo as well, just didn't have it on me last night so ended up doing about 50 miles working on my Rev Counter.
Rgds,
Shaun+

[AMG Merc]

shaun400se said:

AMG Merc said:

Shaun, maybe you washed the car recently and water sprayed inside the front right wheel where the speedo sensor is located. Try drying it off with a hair-dryer.

Also, whilst you are speedo-less to avoid more speeding fines use your SatNav speed display.

Thanks AMG Merc, I'll try that, so it's front offside wheel then?......any idea what it looks like i.e. is it obvious what it is? Will also take tip on Satnav speedo as well, just didn't have it on me last night so ended up doing about 50 miles working on my Rev Counter.
Rgds,
Shaun+

Sure, look at the rear of the wheel and trace a thin single Black cable to a 1.5inch rod like sensor - that's it.

[JAZ 34]

Shaun,

I had exactely the same thing.

I got my local garage to replace it for me!

Jamie

[DanH]

AMG Merc said:

Shaun, maybe you washed the car recently and water sprayed inside the front right wheel where the speedo sensor is located. Try drying it off with a hair-dryer.

Has that ever worked for anyone? It certainly didn't for me!

[Mr Noble]

Never worked for me. I've had to have mine replaced twice. Luckily I have a warranty that does it for free!!

[shaun400se]

Thanks for all your tips - and sob stories fellas. Sounds like contrary to what Peter Smith Sportcars told me a year ago when taking my M12 in to get the same thing done, that it IS indeed a common Noble ailment. Funnily enough I DID jet wash the arches and just inside the clams last time I had the car out 4-5 weeks ago, because I'd been sent on a diversion on the Aberdeenshire roads which took me through farmyard territory which left the car in a right old state (after our last meet Janmie!). Anyway, I'll get the old hairdryer out this weekend and see if it works, otherwise it looks like getting booked in for a replacement.

Thanks again guys.
Shaun+

[DanH]

shaun400se said:

Thanks for all your tips - and sob stories fellas. Sounds like contrary to what Peter Smith Sportcars told me a year ago when taking my M12 in to get the same thing done, that it IS indeed a common Noble ailment. Funnily enough I DID jet wash the arches and just inside the clams last time I had the car out 4-5 weeks ago, because I'd been sent on a diversion on the Aberdeenshire roads which took me through farmyard territory which left the car in a right old state (after our last meet Janmie!). Anyway, I'll get the old hairdryer out this weekend and see if it works, otherwise it looks like getting booked in for a replacement.

Thanks again guys.
Shaun+

I'd save yourself the effort on the hairdryer front

[NobleSteed]

M12s were on the offside front wheel, M400s went to the nearside front. It is obvious anyway whan you look. I understand the sensor size changed too but not dead certain on that one

Cheers

Richard

[shaun400se]

Cheers for that NobleSteed - I'll be taking a look tomorrow sometime!

Rgds,
Shaun+

[Shaun400se]

....and amazingly????

Lovely sunny warm day here in Aberdeen, so thought I'd 'unleash the beast' on the nortth Deeside roads through to Banchory this morning to get my son to his football (any excuse eh?).

Guess what? The speedo is absolutely fine, spot on, no wavering, no erratic behaviour, and from what I can see (by following other cars in restricted speed limit areas), it's reading perfectly.

Shaun+