INSIGNIA 09 rear wheel ABS sensor fault

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INSIGNIA 09 rear wheel ABS sensor fault

Postby GRUSS » Fri Jan 20, 2012 6:53 pm

I've only just got a laptop sorted for my new scope so havent had a chance to use it yet so forgive me for any ignorance...

At work today i got a vauxhall insignia 09 with the ABS light on.The DTC would clear but the brake pedal would pulse under braking (light or hard) and the light would come back on. C0050 rear right wheel speed sensor signal erratic.

There are known water ingress issues with the block connectors in the rear arches so i investigated there first. Everthing looked ok visually. I removed the sensor from the hub and that too looked ok.
I checked the wiring with the sensor plugged in back probing with my DMM. 12V down one wire with no short to earth then carried out a 'dynamic' test on the signal wire. 7-14Ma spinning the wheel.
I then repeated the test up at the ABS control unit with the same result, also tested the NSR speed sensor which was also the same.
I then reported back to VX technical who wanted me to swap the signal wires in the ABS plug, i decided against this as room is very tight so for ease and speed, swapped the rear sensors over.
Cleared the DTC and re-roadtested, same DTC came back so i suspect its the actual bearing as the magnetic pick-up is built into it. I will fit one in the morning.

my question is, if i had my scope obviously i could check the signal from the sensor. How would i workout if the sensor was faulty or the magnetic-pick up? would it be obvious if i looked at the waveform?

thanks in advance
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby Robski » Sat Jan 21, 2012 9:03 am

my question is, if i had my scope obviously i could check the signal from the sensor. How would i workout if the sensor was faulty or the magnetic-pick up? would it be obvious if i looked at the waveform?


The clue is in the DTC description ' erratic ' . The signal would be all over the place rather than a uniform trace.

If i get a bit of time i'll grab a capture from an active WSS.

http://www.vsm.skf.com/~/media/Files/en ... 16_22.ashx
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby GRUSS » Sat Jan 21, 2012 3:17 pm

I realise the big clue from the DTC but how would I determine which was at the fault, the sensor or the bearing?
I fitted the bearing this morning and it has fixed the problem. I should of scoped it but didn't have time as the customer wanted in first thing.
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby GRUSS » Thu Feb 09, 2012 8:25 pm

Any more comments on this? just looking for someone to explain how i would determine a faulty sensor or a bearing (newer second generation type) by looking at the waveform?
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby Alan » Thu Feb 09, 2012 8:37 pm

When measuring the signal, spin the wheel around a few times. If you see a repeating pattern with something odd once per revolution then its the bearing.

If its not switching at all or looks random / weird then its more likely to be the sensor.

Of course if you swap over the sensors then if the fault follows the sensor...
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby GRUSS » Fri Feb 10, 2012 5:17 pm

alan wrote:When measuring the signal, spin the wheel around a few times. If you see a repeating pattern with something odd once per revolution then its the bearing.

If its not switching at all or looks random / weird then its more likely to be the sensor.

Of course if you swap over the sensors then if the fault follows the sensor...


Thanks for the reply Alan, you confirmed what I was thinking. :D
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby Robski » Fri Feb 10, 2012 7:24 pm

Thanks for the reply Alan, you confirmed what I was thinking.


So if it looks random your happy to fit a sensor ?
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby GRUSS » Fri Feb 10, 2012 8:12 pm

Robski wrote:
Thanks for the reply Alan, you confirmed what I was thinking.


So if it looks random your happy to fit a sensor ?


I would scope the nsr and it that looked ok fit the suspect osr sensor to the nsr and like Alan had said, see if the fault follows. If it does than its probably the sensor. I had already checked the wiring from rear to the front.
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby Robski » Fri Feb 10, 2012 8:23 pm

I would scope the nsr and it that looked ok fit the suspect osr sensor to the nsr and like Alan had said, see if the fault follows. If it does than its probably the sensor. I had already checked the wiring from rear to the front.


So why did you ask ?
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Re: INSIGNIA 09 rear wheel ABS sensor fault

Postby GRUSS » Fri Feb 10, 2012 8:26 pm

I never got a chance to scope the sensor, my original question was if I did scope the sensor how would I determine which was bad, the sensor or the bearing. Have another read of the thread to refresh your memory.
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