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Old 18th November 2023, 07:57   #11
SD1too
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I've got red ABS, yellow brake, and yellow traction control lights. And no bl@@dy speedo!
Ahh, thanks for the extra information Iain which helps.

With three warning lights it sounds to me as if you have a more widespread ABS problem rather than it being limited to the front right-hand sensor. I had the same indication earlier this year and it was excessive brake dust in the rear drums producing interference on the sensor signal(s). T4 reported the interference but the location wasn't specified so a bit of detective work was necessary!

In contrast, when my front ABS sensor leads were damaged by contact with the wheel (have you checked this?) I recall that only the ABS warning light was illuminated.

Arctic's advice is confirmed by RAVE which says that following repair of a sensor fault, the warning lamp will remain illuminated until vehicle speed exceeds 7.5 mph (12 kph) so a road test is essential.

Simon
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Old 18th November 2023, 12:24   #12
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Aye, it's been driven. No joy...
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Old 18th November 2023, 13:41   #13
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Okay. Been poking...
Sensor unplugged, using the tails from the blue plug off the old sensor, plugged in to the line to the ABS ECU.

From thread 133814 above...

DMM test. I should have 12v on one line to the ABS sensor, after self-test, and between 0.6v and 1.7v on the other.
I've got 7.56v on the 12v line, 8v on the other.
Looks to me like the ABS ECU is goosed!
Please tell me I'm wrong...

I have a donor car, I can take the ABS ECU from that, but it's a 1.8T engine, no TC, will it work with the diesel and TC?
Iain
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Old 18th November 2023, 19:10   #14
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I've got 7.56v on the 12v line, 8v on the other.
Looks to me like the ABS ECU is goosed!
Please tell me I'm wrong...
What is your battery voltage Erik?
Have you also measured the voltages to the other three wheel sensors as a comparison? What are they?
Have you rotated the road wheel and observed the variation in voltage? RAVE says this should be a square wave between 0.5 v and 3.0 volts. Perhaps this is measured across the two sensor wires and not between each and earth (I don't know)?
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I have a donor car, I can take the ABS ECU from that, but it's a 1.8T engine, no TC, will it work with the diesel and TC?
No. The ECUs with and without traction control are different internally.

Erik; beware of jumping from one dramatic diagnosis to another.
A Testbook session would be useful. Do you have any plans to arrange that? What about a different third party code reader?
I asked if you have checked the front ABS sensor leads for physical damage. Please let me know the answer.

Simon
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Old 18th November 2023, 21:51   #15
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Simon, only T4 I know of this side of the North Sea is on the east coast of Sweden. I'm on the west coast of Norway....2000km round trip, er, maybe not! :-)
Iain
I wonder who that could be

Agree with Simon, don't jump to conclusions esp that the ABS module is defective. I recently worked on a very soggy V6 that had a Christmas appearance on the IPK, everything possible was lit up. The Bosch centre in Stockholm condemned the ABS module and wanted to send it to Holland for repair. The SRS fault was real enough, the side sensors had got soaked, but the ABS & traction control warnings disappeared when I repaired the broken and corroded earthing points.

You've got Sebastian in Bergen who is quite handy with Toaf, see what leads Toaf can give you. I know that Toaf isn't fully compliant with the 1.8s but very good with V6s and diesels. Testbook is just an earlier version of the T4, so if you can find someone with it and it can handle the CDs, give it a try, but give Sebastian a shout first.

Good luck

Last edited by vitesse; 18th November 2023 at 21:52.. Reason: Hate auto correct
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Old 19th November 2023, 09:42   #16
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Hello, mate!
Wondered if you'd pop up!
Who's Sebastian in Bergen? Don't think I know him...
TOAF doesn't seem to want to connect properly to this car, works fine on the others...
As said above, Smartbox wouldn't communicate with the ABS ECU, and given the voltages from the ECU to the (at least) right front sensor, see above, it does kinda point one way.
Can I use a non-TC ABS ECU on a TC-fitted car, though?
Actually thinking of removing the unit from the donor, plugging it in and seeing if it works, then fitting it somewhere a bit more accessible for the future...
Cheers,
Iain
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Old 19th November 2023, 09:49   #17
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Oops, didn't see SD1too's answer.
So, can't use the donor ECU. Burglar.
Physical damage, not checked the other three, new one on front right. I'll have a look at the others. I can probably do the same voltage test on them, with the spare blue plug and tails, see what I get. Left front suspension arm was replaced, perhaps some damage there...but that wouldn't kill the speedo? And there's the voltages from the front right which are...wrong.
Anyone got a spare TC-fitted ABS ECU :-)
Iain
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Old 19th November 2023, 11:18   #18
SD1too
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Left front suspension arm was replaced, perhaps some damage there...but that wouldn't kill the speedo? And there's the voltages from the front right which are...wrong.
Hi Iain,

My point is that you have more warning lights than a Christmas tree! I don't remember that happening when my front ABS sensors were damaged. However all three warnings (ABS, brake system & TC) did illuminate when the fault turned out to be nothing more than excessive brake dust in the rear drums.
I have offered this experience earlier in your thread so apologies for repeating it but I don't want you to waste a lot of money on an unproven ABS modulator replacement.

As you haven't yet repeated your voltage test on the remaining three ABS sensors, it is surely too early to conclude that the results you have for the OSF are "wrong".

I'd advise being cautious in convincing yourself that the ABS modulator is at fault on the basis of the renewal of one sensor. Note especially what Vitesse has said:
"... but the ABS & traction control warnings disappeared when I repaired the broken and corroded earthing points."

Simon
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Old 19th November 2023, 11:51   #19
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Hello, mate!
Wondered if you'd pop up!
Who's Sebastian in Bergen? Don't think I know him...
TOAF doesn't seem to want to connect properly to this car, works fine on the others...
As said above, Smartbox wouldn't communicate with the ABS ECU, and given the voltages from the ECU to the (at least) right front sensor, see above, it does kinda point one way.
Can I use a non-TC ABS ECU on a TC-fitted car, though?
Actually thinking of removing the unit from the donor, plugging it in and seeing if it works, then fitting it somewhere a bit more accessible for the future...
Cheers,
Iain
Sebastian Tovås, he's the admin guy on the Norwegian Facebook group, lives in Bergen too. I'm sure he'd be willing to pop-over with his copy of Toaf. Toaf is a bit strange sometimes, I recently used it on a 1.8T, I could access the IPK and ABS but not the engine module, however if yours is a diesel then there should be no problem.

Have another read about my recently ABS issues, warnings disappeared once the earthing points were fixed.

And even the traction control unit can illuminate the ABS warning, far more likely than a defective ABS module.

Good luck
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Old 19th November 2023, 19:06   #20
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SD1too, I'll check the other three soon as, but I'm not hopeful. Why would I have battery voltage of 12.7v, with +8v and +7v on the tails from the ABS ECU to the sensor? Odd.
They should read about +12v on the feed and between +0.6 to +1,7 on the other...
vitesse, I'll hunt down the relevant earthing points, and check them.
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