C70 T5 Strange speedo problem!

thad1 · May 10th, 2013, 07:41

When on the motorway the other day I put the cruise on at 70mph and the car started surging slightly, the speedo was moving from 70mph to 75mph, kind of bouncing back and forth as the car surged!

Any ideas?

I have disconnected the abs/tracs as the abs was constantly trying to activate as I drove down the road, I replaced the module but still had the same problem, this makes me think this problem might be to do with the reluctor rings/speed sensor!!

I am hoping someone might be able to point me in the right direction!

Thanks

Luxobarge · May 10th, 2013, 09:15

Front left reluctor ring.

c70t5beater · May 10th, 2013, 17:45

Im another c70 has similar problem. New front reluctor rings fitted 6 months as they where causing low speed abs action.. Around 2 months ago my speedo began to stick to reading too low and then jump to correct speed and bringing on abs, ecu and stc off light! Put it on dice and cleared the abs-0011, abs-0012 left no signal and ecm-510f vss signal too low and it never came back.

This week its now come back with a vengeance. Every statup and move off starts with abs light on, pump seems to do a self check then soon as speedo unsticks to correct reading it stores ecm-510f or P1550 on the elm327.

I then replaced the left front sensor and got rid of left front abs codes but ecm-510 vss signal too low is always there. Im going to check the ohms out of 2 front sensors and straighten up front left reluctor ring as about a 1/4 of it has a 2-3mm squint off the correct resting shoulder on cv joint.

I replaced my abs ecu module part number 9472971 with a used unknown history £20 dismantlers c70, its apparently the more reliable designed 8619538 but the fault remained same, even clearing all with dice correctly it came back soon as speedo jumped.

I can only think ive been very unlucky aind got 2 bad abs modules or the front ring is cauing all this trouble.

I believe the abs module 8619538 is also used in the S60's. A friend of mine has an 01 S60 T5 with no issues so thought i could try mine in his to rule it out as broken.

Very annoying!

May 10th, 2013, 07:41	#1
thad1 Senior Member Last Online: Jan 22nd, 2016 22:48 Join Date: Jan 2012 Location: Banbury	C70 T5 Strange speedo problem! When on the motorway the other day I put the cruise on at 70mph and the car started surging slightly, the speedo was moving from 70mph to 75mph, kind of bouncing back and forth as the car surged! Any ideas? I have disconnected the abs/tracs as the abs was constantly trying to activate as I drove down the road, I replaced the module but still had the same problem, this makes me think this problem might be to do with the reluctor rings/speed sensor!! I am hoping someone might be able to point me in the right direction! Thanks

May 10th, 2013, 09:15	#2
Luxobarge Premier Member Last Online: Apr 26th, 2024 09:37 Join Date: Jan 2011 Location: Horne (Nr. Horley)	Front left reluctor ring. __________________ Some people are like Slinkies, they serve no useful purpose but they still bring a smile to your face when you push them downstairs.

May 10th, 2013, 17:45	#3
c70t5beater Junior Member Last Online: Apr 21st, 2015 21:48 Join Date: Nov 2012 Location: Edinburgh	Same here Im another c70 has similar problem. New front reluctor rings fitted 6 months as they where causing low speed abs action.. Around 2 months ago my speedo began to stick to reading too low and then jump to correct speed and bringing on abs, ecu and stc off light! Put it on dice and cleared the abs-0011, abs-0012 left no signal and ecm-510f vss signal too low and it never came back. This week its now come back with a vengeance. Every statup and move off starts with abs light on, pump seems to do a self check then soon as speedo unsticks to correct reading it stores ecm-510f or P1550 on the elm327. I then replaced the left front sensor and got rid of left front abs codes but ecm-510 vss signal too low is always there. Im going to check the ohms out of 2 front sensors and straighten up front left reluctor ring as about a 1/4 of it has a 2-3mm squint off the correct resting shoulder on cv joint. I replaced my abs ecu module part number 9472971 with a used unknown history £20 dismantlers c70, its apparently the more reliable designed 8619538 but the fault remained same, even clearing all with dice correctly it came back soon as speedo jumped. I can only think ive been very unlucky aind got 2 bad abs modules or the front ring is cauing all this trouble. I believe the abs module 8619538 is also used in the S60's. A friend of mine has an 01 S60 T5 with no issues so thought i could try mine in his to rule it out as broken. Very annoying!

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