Eratic speedo readings...
Eratic speedo readings...
Author
Discussion

satman

Original Poster:

2,455 posts

275 months

Thursday 21st February 2008
quotequote all
Drove the car tonight, first time for a few weeks, and had a small problem after about an hour.

Was travelling approx 80mph, when i noticed the speedo suddenly dropped to 60 then back up again, and repeated this a few times, once dropping to about 30, before setling back at correct speed reading. I did note that the digital speed reading also seemed to drop at same time. When i stopped at home i saw the diagonstic code L on display which from a search found this- "L - Erratic road speed signal input".

Can anyone enlighten me to the cause and is it likely to get worse? Could it be just a 'blip'? More importantly, is it going to be a problem to me as i had planned to use car this weekend on a trip to Isle of Wight...

Any help apprieciated.

andyoleary

1,713 posts

242 months

Thursday 21st February 2008
quotequote all
Sounds like your speedo sensor on the rear axle/diff. Might just be dirty or needing the gap adjusting. If not, it might need replacing.

Plenty of threads on here about this if you want to do a search - I haven't looked at mine personally:

eg: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Andy

satman

Original Poster:

2,455 posts

275 months

Thursday 21st February 2008
quotequote all
thumbup Thanks

SHIFTY

997 posts

265 months

Friday 22nd February 2008
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There were some problems with the earlier speedo sensors the outer sheath is black, new versions now blue. The sensor not only has to have the correct gap but also has to be aligned correctly.

The sensor has a V groove cut into the thread at the sensor end and this must be vertical for the sensor to detect correctly, mine had come loose the sensor had turned only by 45" and the results were no speedo, onerous readings, etc etc. Realigned correctly, gapped to 1MM tightened up and and now perfect.

Easy to do if you jack the car up and may save you £130



Edited by SHIFTY on Friday 22 February 07:46

ec1 eex

400 posts

271 months

Friday 22nd February 2008
quotequote all
andyoleary said:
Sounds like your speedo sensor on the rear axle/diff. Might just be dirty or needing the gap adjusting. If not, it might need replacing.

Plenty of threads on here about this if you want to do a search - I haven't looked at mine personally:

eg: http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Andy
I started the thread andy referred to. Changing the transducer fixed it and I haven't had any problems since.
Phil

satman

Original Poster:

2,455 posts

275 months

Friday 22nd February 2008
quotequote all
Thanks guys...wont get chance to check out before i leave to go to Isle of Wight, so hopefully it was a one off that was caused by a bit of dirt...if not itll be up on a ramp next week.

Keep an eye out for me..on M3 en route to Portsmouth this morning and hooning round Island over weekend biggrin