P38A ABS & TC fault. - FIXED!

tomcat59alan · Mar 18, 2020

DanClarke said:
UPDATE:
Part arrived at lunchtime.
Did some further testing before fitting it (Front Right) sensor.
Pulled the connector on the Front left and probed for voltages there. Same as the Front Right Socket 3.3V on one pin.
Measured the resistance across the pins of the new part 1.4kOhms.
Pulled the old existing ABS sensor off the front right and measured the resistance across that, did not register any reading (other than Out of Range) until I put it on the 2Meg Ohm range , at which point it said 1.04 megOhms..
Put the new sensor on, cleared the faults with Nanocom, no more ABS/TC fault messages on ignition on. Test drove and all OK.
So definitely a duff sensor. Why it went kaput after a thrash I don't know.

Q. Why/how would thick black sooty grease get deposited on the end of a sensor? Does this imply a leak from the hub?
Other bad news to come.... the suspension bags look really gnarly and cracked.

Sounds like the wheel bearing is loosing its grease and collecting brake dust time for a new bearing.

Datatek · Mar 18, 2020

DanClarke said:
One other minor detail was that the 3 original ABS Sensors reported a perfect 2.33V in Nanocom on stationary vehicle ignition on (only time the Wabco-D module can be contacted by Nanocom). The new OEM one only reports 2.13V.
The Wabco ECU seems not to mind though.

The static voltage is only part of the story, it will be the peak to peak waveform that matters, you an only check that with a scope

Grrrrrr · Mar 19, 2020

tomcat59alan said:
Sounds like the wheel bearing is loosing its grease and collecting brake dust time for a new bearing.

There should be grease in there already, so it cab catch the brake-dust! Trying to remember what type it says in RAVE. Probably the lithium stuff.

tomcat59alan · Mar 19, 2020

Grrrrrr said:
There should be grease in there already, so it cab catch the brake-dust! Trying to remember what type it says in RAVE. Probably the lithium stuff.

Don't think so mate, the wheel bearings are sealed units as are the cv joints unless the c v boot is split .

wammers · Mar 19, 2020

There should be no grease at all in and around the reluctor ring.

tomcat59alan · Mar 19, 2020

wammers said:
There should be no grease at all in and around the reluctor ring.

I didn't think so, how are you Tony?

wammers · Mar 19, 2020

tomcat59alan said:
I didn't think so, how are you Tony?

Not bad up and down as usual. Hows you?

Henry_b · Mar 19, 2020

The clamps holding my CV boots rusted off.
Causing grease to go everytwhere, maybe worth checking to see if the clips are still doing their thing.

tomcat59alan · Mar 19, 2020

wammers said:
Not bad up and down as usual. Hows you?

Always in the sh1t just the depth varies, you know what it's like.

Keep safe mate.

Grrrrrr · Mar 19, 2020

wammers said:
There should be no grease at all in and around the reluctor ring.

Not the reluctor ring. Where the sensor pushes into the bush.

wammers · Mar 20, 2020

Grrrrrr said:
Not the reluctor ring. Where the sensor pushes into the bush.

Yes there should be grease in there, Copaslip is ideal.

martyuk · Mar 25, 2020

Grrrrrr said:
Yes, you're right and I think it was the WABCO-D that did it but not sure which screen. @martyuk did a post on it somewhere.

The fault codes that Nanocom reports from the ABS ECU are true to what corner is is... so if Nanocom shows a fault reported on Front/Right, then it IS Front/Right where the fault lies.

The discrepancy on Nanocom comes from the live data screens - where it shows the data from each sensor, but the labels are wrong on 3 of the corners. I dug out my notes, and these are what Nanocom says vs the actual sensors on the vehicle:

Front/Right on Nanocom IS Front/Right on the vehicle (the ONLY one which is correct)
Rear/Right on Nanocom is Front/Left on the vehicle
Rear/Left on Nanocom is Rear/Right on the vehicle
Front/Left on Nanocom is Rear/Left on the vehicle

So if Nanocom in the faults section said there was an issue with the Rear/Right sensor on the vehicle (for example)... then this WOULD be the Rear/Right vehicle sensor - BUT if you went into the live data to look at the sensor voltage, you would see something wrong with the voltage reading on what Nanocom says is the Rear/Left sensor.

There are a couple of labelling discrepancies in the HEVAC too (from memory the LH/RH sides for temp and seat heaters). I did mention this to BBS a few years ago to ask if the labelling could be updated in a future Nanocom software version, but to my knowledge this hasn't yet happened.

The difference in voltage showing on the ABS ECU is probably due to a slightly different resistance of the aftermarket sensor. But as long as it's close and not reading 0V, then the ECU should pick up on a decent waveform from it and be happy.

Pete The Biker · Mar 26, 2020

DanClarke said:
.......So definitely a duff sensor. Why it went kaput after a thrash I don't know......

The wife's Peugeot managed to send her sensor kaput while parked on the drive!

Pete

Mark Piercy · Mar 27, 2020

Pete The Biker said:
The wife's Peugeot managed to send her sensor kaput while parked on the drive!

Pete

On some cars, if the handbrake is put on just so it illuminates the park lamp.
Each wheel can be turned and a warning will beep as car thinks its moving with the handbrake on! A duff sensor won't tell it its moving. Only on some cars /models.

Pete The Biker · Mar 27, 2020

Mark Piercy said:
On some cars, if the handbrake is put on just so it illuminates the park lamp.
Each wheel can be turned and a warning will beep as car thinks its moving with the handbrake on! A duff sensor won't tell it its moving. Only on some cars /models.

Hi Mark. No, the sensor was open circuit, so got ABS warnings as soon as the ignition was turned on. The car hadn't moved at all!

Pete

DanClarke · Mar 27, 2020

martyuk said:
The fault codes that Nanocom reports from the ABS ECU are true to what corner is is... so if Nanocom shows a fault reported on Front/Right, then it IS Front/Right where the fault lies.

The discrepancy on Nanocom comes from the live data screens - where it shows the data from each sensor, but the labels are wrong on 3 of the corners. I dug out my notes, and these are what Nanocom says vs the actual sensors on the vehicle:

Front/Right on Nanocom IS Front/Right on the vehicle (the ONLY one which is correct)
Rear/Right on Nanocom is Front/Left on the vehicle
Rear/Left on Nanocom is Rear/Right on the vehicle
Front/Left on Nanocom is Rear/Left on the vehicle

So if Nanocom in the faults section said there was an issue with the Rear/Right sensor on the vehicle (for example)... then this WOULD be the Rear/Right vehicle sensor - BUT if you went into the live data to look at the sensor voltage, you would see something wrong with the voltage reading on what Nanocom says is the Rear/Left sensor.

There are a couple of labelling discrepancies in the HEVAC too (from memory the LH/RH sides for temp and seat heaters). I did mention this to BBS a few years ago to ask if the labelling could be updated in a future Nanocom software version, but to my knowledge this hasn't yet happened.

The difference in voltage showing on the ABS ECU is probably due to a slightly different resistance of the aftermarket sensor. But as long as it's close and not reading 0V, then the ECU should pick up on a decent waveform from it and be happy.

Thanks @martyuk its good to know.

Doolinjames · Jul 4, 2024

Hi I have a abs light on 1 of my p38s nanacom says right hand sensor gap but ring was damaged put new ring on and new sensor still got fault.the other problem i have is when i press the brakes there is a grunting noise when I press the brake pedal sometimes it goes away.now my nanacom no comunication coming up.thanks in advance

doriz · Jul 4, 2024

Doolinjames said:
Hi I have a abs light on 1 of my p38s nanacom says right hand sensor gap but ring was damaged put new ring on and new sensor still got fault.the other problem i have is when i press the brakes there is a grunting noise when I press the brake pedal sometimes it goes away.now my nanacom no comunication coming up.thanks in advance

Fuse box issues?

Datatek · Jul 4, 2024

Check the ECU for dampness

Doolinjames · Jul 4, 2024

A new fuse box in this car.

P38A ABS & TC fault. - FIXED!

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