new abs sensor high at 1135 ohms and abs ECU checks

John Plum · Post by **John Plum** » 28 Oct 2014, 21:33

I replaced a front abs sensor which gave zero resistance, with a new one supposedly matched for the car, and noticed this new one has a resistance which is slightly higher at 1135 ohms than the usual quoted 1080 ohms.

Do you know, Is this discrepancy likely to pass the static abs ECU checks, or adversely affect them? (I haven't got her rolling yet, to try clearing the abs fault light - waiting for a hydraulic pipe, to fit).

While we're here, could you tell me where the abs relay is found on a Xantia II?

(not sure I'm getting any abs light blinks, unless they are very fast, and I miss them).

cheers,
John

Post by **CitroJim** » 29 Oct 2014, 17:34

I take it you've not replaced it yet then John.. I must say it does seem a bit high but then again I've seen them a bit off resistance-wise and they seem OK in use... The S2 ECU may be a bit cleverer than just measuring the DC resistance of a sensor. It may be able to take a stab at measuring its impedance.

Is it a very economically priced one from ebay by any chance?

Best is to dis the old one at the connector and just loosely connect the new one to see if it passes. Then you've not wasted time properly fitting it if it is duff..

I've found the el-cheapo ebay ABS sensor offerings don't have a long life at all. One OI fitted to my S2 lasted about a year before going a bit intermittent and then dying totally.

I'm not even sure the S2 has an ABS relay. Never consciously noticed one where the S1 has it in the corner of the engine bay fuse box. If there is one it'll be dark green.

S1 and S2 ABS ECUs are very different and I'm not sure you see distinct flashes on an S2 as you do on the S1. I've never noticed them on my S2...

John Plum · Post by **John Plum** » 29 Oct 2014, 17:44

Thanks for thar considerate reply Jim.
Yes I've fitted it fully, but cannot roll until I get and fit a rear brake pipe. But I can't see how it can pass loosely connecting, because I think I have an abs lockout, and it needs to roll to clear that.

Yes it's a cheapo from eBay. Oh well, perhaps it may work, but not for long.
I'll spend more next time. It wasn't difficult at all to fit, really
My new 10mm worn bolt extractor socket came in handy removing the old one. A cinch. Glad I ordered the set - a draper one from Amazon.

I feel reassured by what you say about S2 blinking and also the use of sensors a bit off resistance-wise.
John

Hell Razor5543 · Post by **Hell Razor5543** » 29 Oct 2014, 17:50

I know that when we replaced the reluctor rings on Gracie CitroJim was able to get a speed reading on his ELIT system (with me just rotating the wheels by hand). I don't know if the Lexia would do the same.

Post by **CitroJim** » 29 Oct 2014, 17:52

Hell Razor5543 wrote:I don't know if the Lexia would do the same.

Yes, it'll do exactly the same James..

John Plum · Post by **John Plum** » 29 Oct 2014, 17:54

Yes I could do with software. Can you get it for a Macintosh - I think not?

Hell Razor5543 · Post by **Hell Razor5543** » 29 Oct 2014, 17:54

In that case it could be worth spinning the wheel by hand, to see if the ABS system accepts there is a sensor in place (or to see if the Lexia sees it and can convince the ABS system it is back in play).

John Plum · Post by **John Plum** » 29 Oct 2014, 17:56

I'll give it a go. By hand eh, so that exceeds the 20 kph threshold (or whatever it is)?

Hell Razor5543 · Post by **Hell Razor5543** » 29 Oct 2014, 18:02

I don't know how the Lexia system would manage it. I also don't know if it would want all wheels turning. I do know that, when the Lexia found I had a failed O/S/R sensor, there was the option to clear the fault, but (as I had not yet replaced the sensor) this failed.

I do not believe there would be a Mac version of the Lexia.

Post by **CitroJim** » 29 Oct 2014, 18:02

Problem is I think all wheels need to spin at the same speed above 20 kph to do the reset..

Is there a Lexia-carrying member near you John who could do the honours for you?

John Plum · Post by **John Plum** » 29 Oct 2014, 18:05

Ah!
Yes DickieG, about 10- 15 miles away, but I'd need to get her rolling anyway, Ho Ho

John Plum · Post by **John Plum** » 29 Oct 2014, 18:07

Patience is a virtue, oh yes. I'll wait, by the fire, drinking tea and scoffing cake.
(That's not to delay things though).

Hell Razor5543 · Post by **Hell Razor5543** » 29 Oct 2014, 18:09

I am in Reading, I have a Lexia, and I have limited experience of it. I have got to replace Gracies' N/S/F brake calliper though, as the handbrake lever is not returning properly. I have a replacement, but I wasn't able to fit it today.

John Plum · Post by **John Plum** » 29 Oct 2014, 18:17

I think James, you mean you'd come over to help out if or when able: that's swellegant.
I'd say, no problem really I'll wait and see result on road first.
However, I'd appreciate a Lexia session at some point since taking her over earlier this year - may even be necessary quite soon if it doesn't clear with this replacement.
I'll keep your kind offer in mind.
Good luck.
John

Hell Razor5543 · Post by **Hell Razor5543** » 29 Oct 2014, 18:21

That is what I meant.

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