Do ABS sensors need to be in situ ...

grumpyshouse · 21st November 2012, 21:36

to pass the 'self test' on ignition?
I have a feeling its the bearing thats iffy but thought i'd try a new sensor first as its a lot simpler and quicker than changing a hub

i.e. ignition on, abs light comes on , wait 4 secs - should go out. mine doesnt!

can I eliminate a faulty sensor but simply plugging a new one in or does it need to be fitted into its housing and the correct distance from its reluctor magnet thingy? even though the wheel is not rotating?

thanks in advance again

rover54 · 21st November 2012, 21:55

Quote:

Originally Posted by grumpyshouse

to pass the 'self test' on ignition?
I have a feeling its the bearing thats iffy but thought i'd try a new sensor first as its a lot simpler and quicker than changing a hub

i.e. ignition on, abs light comes on , wait 4 secs - should go out. mine doesnt!

can I eliminate a faulty sensor but simply plugging a new one in or does it need to be fitted into its housing and the correct distance from its reluctor magnet thingy? even though the wheel is not rotating?

thanks in advance again

I once just just plugged a sensor in and the ABS passed the self-test, so I would say yes. Try it and see.

T-Cut · 21st November 2012, 21:57

I think the sensor is more likely to be at fault than the reluctor ring. From what I've read, plenty of sensors get replaced to fix ABS issues, but not many bearings.

TC

James.uk · 22nd November 2012, 00:34

I would think the sensor needs to be in place before it can work... No point in having a magnetic ring otherwise...

...

75tourer · 22nd November 2012, 01:20

Should be ok just plugging the sensor in. Sensor is not powered but works on an induced pulse from the magnetic ring with a series of on/off as each segment passes the sensor during rotation. Plugged in only will replicate an off state and pass test.self test with a faulty sensor will show up an open circuit and keep light on dash illuminated

Plezier · 22nd November 2012, 01:32

Pardon me but I understand the Hall effect sensors are powered and have a voltage running through them.

This is what the static self test is testing that all sensors return the correct voltage. The system then does a running test at a certain distance speed which tests the feed back from the rings.

Simon.h · 22nd November 2012, 04:01

If you have fitting a new wheel.sensor, the self check needs to now see all wheels spinning at the same speed and this can only be done by driving it.

grumpyshouse · 22nd November 2012, 09:03

Thanks gents
when i first investigated the abs light on issue (and no speedo) i discovered that the sensor plug was not fully pushed home. parted cleaned and reconnected the light then went out. Result!

Put the wheel back on ready for a road test of the speedo and the light is back on

I did the voltage test and i have 12v on the y/b and 1.7v on the other - but no fluctuation, which leads me to think its the bearing at fault So have ordered a s/h hub etc just waiting for delivery.
Are my assumptions correct?

I have tried a new sensor (not oe) plugged that in but still the light remains illuminated - hence the question.

HarryM1BYT · 22nd November 2012, 09:23

Quote:

Originally Posted by grumpyshouse

Thanks gents
when i first investigated the abs light on issue (and no speedo) i discovered that the sensor plug was not fully pushed home. parted cleaned and reconnected the light then went out. Result!

Put the wheel back on ready for a road test of the speedo and the light is back on

I did the voltage test and i have 12v on the y/b and 1.7v on the other - but no fluctuation, which leads me to think its the bearing at fault So have ordered a s/h hub etc just waiting for delivery.
Are my assumptions correct?

I have tried a new sensor (not oe) plugged that in but still the light remains illuminated - hence the question.

My understanding is that simply plugging a sensor in, it should pass the static test at switch on, but will obviously fail the dynamic test as the car is driven.

There are lots of reports of new none OEM ABS sensors failing as soon as installed - exactly what you seem to be finding.

grumpyshouse · 27th November 2012, 17:13

I can confirm that it does indeed pass the self test without being fitted or earthed!

I can also confirm zods law - just because the speedo isnt working doesnt mean its the front right thats faulty.

It turned out that my speedo didnt work because of the bearing/ magnet on the right front, but the abs light not passing the self test was down to the rear right sensor having an iffy connector under the back seat, possibly down to the extreme damp caused by unconnected rear sunroof drains

21st November 2012, 21:36	#1
grumpyshouse Avid contributor Rover 75 Join Date: Nov 2012 Location: Llanelli Posts: 174 Thanks: 1 Thanked 0 Times in 0 Posts	Do ABS sensors need to be in situ ... to pass the 'self test' on ignition? I have a feeling its the bearing thats iffy but thought i'd try a new sensor first as its a lot simpler and quicker than changing a hub i.e. ignition on, abs light comes on , wait 4 secs - should go out. mine doesnt! can I eliminate a faulty sensor but simply plugging a new one in or does it need to be fitted into its housing and the correct distance from its reluctor magnet thingy? even though the wheel is not rotating? thanks in advance again

22nd November 2012, 01:32	#6
Plezier I really should get out more....... Mercedes C Class CDI estate (2003) Join Date: Sep 2012 Location: Gradina Posts: 2,652 Thanks: 62 Thanked 137 Times in 119 Posts	Pardon me but I understand the Hall effect sensors are powered and have a voltage running through them. This is what the static self test is testing that all sensors return the correct voltage. The system then does a running test at a certain distance speed which tests the feed back from the rings. __________________ Classic SE CDT sadly lost in a severe collision.

22nd November 2012, 04:01	#7
Simon.h This is my second home Previously owned- MG ZT V6 160 Y plate Lpg, MG ZT 190 2003 In Rare Celestial Factory Ordered Lpg MG Join Date: Mar 2010 Location: Calne Posts: 4,531 Thanks: 8 Thanked 116 Times in 108 Posts	If you have fitting a new wheel.sensor, the self check needs to now see all wheels spinning at the same speed and this can only be done by driving it. __________________ Previously owned- MG ZT V6 160 Y plate Lpg, MG ZT 190 2003 In Rare Celestial Factory Ordered Lpg MG ZT 190 2004 lpg

27th November 2012, 17:13	#10
grumpyshouse Avid contributor Rover 75 Join Date: Nov 2012 Location: Llanelli Posts: 174 Thanks: 1 Thanked 0 Times in 0 Posts	I can confirm that it does indeed pass the self test without being fitted or earthed! I can also confirm zods law - just because the speedo isnt working doesnt mean its the front right thats faulty. It turned out that my speedo didnt work because of the bearing/ magnet on the right front, but the abs light not passing the self test was down to the rear right sensor having an iffy connector under the back seat, possibly down to the extreme damp caused by unconnected rear sunroof drains __________________ [SIGPIC][/SIGPIC]

21st November 2012, 21:57	#3
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	I think the sensor is more likely to be at fault than the reluctor ring. From what I've read, plenty of sensors get replaced to fix ABS issues, but not many bearings. TC

22nd November 2012, 00:34	#4
James.uk Passed Away 2002 Pale Blue. Rover 75 CDTi Connoisseur auto. 170K miles Join Date: Dec 2008 Location: Near the M67. Posts: 14,509 Thanks: 199 Thanked 585 Times in 397 Posts	I would think the sensor needs to be in place before it can work... No point in having a magnetic ring otherwise... ...

22nd November 2012, 01:20	#5
75tourer Loves to post Rover 75 CDT Tourer Auto Join Date: Nov 2010 Location: Dundee Posts: 285 Thanks: 40 Thanked 13 Times in 9 Posts	Should be ok just plugging the sensor in. Sensor is not powered but works on an induced pulse from the magnetic ring with a series of on/off as each segment passes the sensor during rotation. Plugged in only will replicate an off state and pass test.self test with a faulty sensor will show up an open circuit and keep light on dash illuminated

22nd November 2012, 09:03	#8
grumpyshouse Avid contributor Rover 75 Join Date: Nov 2012 Location: Llanelli Posts: 174 Thanks: 1 Thanked 0 Times in 0 Posts	Thanks gents when i first investigated the abs light on issue (and no speedo) i discovered that the sensor plug was not fully pushed home. parted cleaned and reconnected the light then went out. Result! Put the wheel back on ready for a road test of the speedo and the light is back on I did the voltage test and i have 12v on the y/b and 1.7v on the other - but no fluctuation, which leads me to think its the bearing at fault So have ordered a s/h hub etc just waiting for delivery. Are my assumptions correct? I have tried a new sensor (not oe) plugged that in but still the light remains illuminated - hence the question.