Thread: Method of checking wheel speed sensor fault

Originally Posted by LandyAndy

The speedo reads 120kmh at idle in fith!!!!!.Confused!!!!
Andrew

That's about right. 120 divided by 4 (ony 1 of the 4 wheels is turning so its travelling 4 X as fast as it would normally) = 30.
5th gear 40kph / 1000rpm = 30kph for 750rpm.
I'll buy that.

That is my thought too Greame,it was suggested by a member that a wheel sensor reading that sort of speed is faulty,the same person also suggests that the skiding wheel has the faulty sensor.My opposite on the same axle skids.
Was hoping Pedro discovers the same as I have so in future Pedro and myself can pass the correct info on to D2 owners as its such a common fault.
Ive got a secondhand sensor coming,will see if it fixes everything.
Thanks
Andrew

It would be good to determine a rule for identifying which wheel is the culprit. But having a wheel doing 120kph whilst idling on a block is a bit scary. Maybe 1st gear is a safer option.
Good luck with the research.

hmm, I must be getting old,,
I just let in idle in D


and it read,, oh around 20kph??
or should I say 3 did.

will need a spotter for the brake test,, so it might have to wait till the weekend,,

Seems like I need to look at how i present some of my info.....

Originally Posted by LandyAndy

I did the skid test,found that the right rear skided.
OK decided to clean that sensor again,jacked up the rr with the trolley jack pushed the garden hose up where the sensor wire goes and turned the wheel whilst the water was running.Started the car up eased it into gear,speedo works!!!!.
Then repeated the same on the left rear,NO SPEEDO!!!!! found the culprit,the left rear sensor or a wiring fault for the left rear sensor.The fronts both made the speedo work.
The speedo reads 120kmh at idle in fith!!!!!.Confused!!!!
Andrew

When i replied

Originally Posted by Blknight.aus

that sounds like a dud sensor, the computer averages out the wheel speeds to get vehicle speed and ignores any that are obviosuly telling fibs

to that I was intending that to mean that the sensor that wasnt giving a reading was dud and that under normal circumstances the computer will average out all the working sensors (for when your cornering or have a wheel spinning/slipping)

Hi Dave
No agro intended.
From Pedros/mine and anybody who can hop in with the same issue. Im hoping to stay to others in the future,do a good skid in your D2 note the skidding wheel.Go to the shed jack the opposite wheel on the same axle and discover no speedo reading.Then repeat for the others and hopefully find that the other 3 have the speedo working.
The problem then lies with the sensor with no speed reading despite passing the resistance value.Wont know till I replace the sensor I belive is faulty,but all seems to make sense,
Is the Defender a true 4 channel ABS system as the D2 or just front rear 2 channel ABS as other cars have???
Andrew

no aggro intended I reread it then had the wife read it and she mis-interpreted it the same way.. so rather than edit I had a crack at trying to explain it properly

ITs a true 4 channel abs as it uses the same sensors to control traction control and the ABS/Tc pump block has 4 seperate oulets, one for each wheel..


but I have a theory on the wheel skidd thing...

what if a faulty sensor on one wheel disables that axle. then it will come down to normal physics as to which wheel will slip first. the non effected axle will have abs so wont slip but the effected axle will be a different story, what If I jagged it to get the wheel with the crook sensor to skid and you hooked it the other way?....

just pulled the sensor out,,,
and everyone can stop thinking "a good hose out" will fix this

some iron type filings on the end, but thats all, end was clean otherwise.
cleaned and replaced and made no difference,,

am ASSUMING I will be doing a brake test around lunchtime today--