On my P38 the ABS light stays on the dash until I've driven above 5mph or somesuch. Maybe some distance. Maybe yours does something similar and when the light goes out the sensor readings stop?
As for the 47V. I know some systems convert the voltage to a range between 0 and 255. So, that than volts, could it be 47/255?
Just thought I'd add to the general confusion!
DM68
Active Member
Right, this is my second attempt at a reply, first one timed out.
Short version DSC working,as Saint V8 suggests i think its either ABS sensor/ecu.
DSC,HDC and ABS are all interlinked if one isn't working air suspension ecu cant get a correct reading so throws a fault, if often enough throws hardfault. Your OSR isn't getting height reading, so points to this.
Either ABS sensor got dislodged/knocked when you did work on it recently or your ABS ecu has got damp. Volts to H sensors is 5v with return of 0.5-4.5 so 3 are right ,fourth needs checking,cleaning or refitting. Front heights are ok within 20mm of hardfault height,rear cant comment because dont know how its been calibrated
sestorious
New Member
Right, so in a nutshell re check height sensor fitment an clean plugs an possible change all four ABS sensors an make sure fitted properly an plugs clean wipe all faults an try again ??? PS when i start cqr from cold can hear a ticket at rear end sounds like a pump starts slow an gets quicker then stops wats that ????
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sestorious
New Member
Wat u reckon to my last post mate ? Shall i try 4 new abs sensors ? Lol !
Does your speedo work correctly ??
You say all the warnings come up when you go over a certain speed...what speed is that, and does the speedo work correctly through all speed ranges??
Reason I ask is the speedo gets the speed signal from the ABS ECU which in turn takes the vehicle speed from the LH Rear ABS Sensor....
So if your speedo is working correctly, I would imagine your ABS system is fine....and I take it there are no faults logged in the ABS system at all???
sestorious
New Member
Speedo does work ( whether its the real speed I don't know ) an the only fault in abs was 8a air susp can error ? The readings I took during ABS test eg they increased with speed but stopped at 12 mph even though I was still increasing are they right ?
If your speedo works I would think they are working fine.....
OK refresh the brain:
On start up only warning is AIR SUSP. INACTIVE message?
On driving until certain speed then you get ABS/HDC/DSC Faults....what speed is that?
Datatek
Well-Known Member
On my P38 the ABS light stays on the dash until I've driven above 5mph or somesuch. Maybe some distance. Maybe yours does something similar and when the light goes out the sensor readings stop?
As for the 47V. I know some systems convert the voltage to a range between 0 and 255. So, that than volts, could it be 47/255?
Just thought I'd add to the general confusion!
The systems do convert analogue voltages to digital values between 0 & 255 but these are numbers based on an 8 bit digital byte, they are not voltages and cannot be measured with a DVM
sestorious
New Member
Ok saintv8, on start up "air susp inactive" an that stays on. When hitting motorway speeds of approx 60-70mph for a length of time such as 5-10mins usual suspects come on HDC/ABS/DTC ? Stay on till ignition off then on start up GONE ? car sat level slightly low ( possibly the hard fault 20mm ) as height indicator on dash not illuminated. Can't afford £100 + vat per hour for stealers to waffle bull poooo ! I've come this far hopefully with your help we can fix this !!
I think the ABS etc systems are going out in sympathy with the EAS Fault and ther eis no issue with the ABS/DSC/HDC system or its sensors....
After replacing the Height Sensors which you say you have done, and the fact they are fitted correctly in comparison to the photos along with the odd readings you are getting...leads me to think it is the EAS ECU....
Now, one thing we could try is make sure the vehicle is sitting reasonably level and disconnect the height sensors and using a Digital Meter set to Resistance (Don't ask me which range I don't know - you will have to try them all) and physically measure the resitance values of each height sensor and see if they are giving a similar reading across the axle (Front readings will be different to the Rear so don't compare those).....if one Height Sensor is giving an odd resistance value...there is most likely the ansower.....if they are all reading roughly and relativley the same....the issue is more than likely the ECU or the wiring from the *odd* sensor to the ECU....
After replacing the Height Sensors which you say you have done, and the fact they are fitted correctly in comparison to the photos along with the odd readings you are getting...leads me to think it is the EAS ECU....
Now, one thing we could try is make sure the vehicle is sitting reasonably level and disconnect the height sensors and using a Digital Meter set to Resistance (Don't ask me which range I don't know - you will have to try them all) and physically measure the resitance values of each height sensor and see if they are giving a similar reading across the axle (Front readings will be different to the Rear so don't compare those).....if one Height Sensor is giving an odd resistance value...there is most likely the ansower.....if they are all reading roughly and relativley the same....the issue is more than likely the ECU or the wiring from the *odd* sensor to the ECU....
Datatek
Well-Known Member
Most DVM ohms ranges are 200; 2k; 20K etc, the 2K range should do the job if the values are similar the the P38, otherwise try the 20K range. If the meter has a 10K range use that.
EAS ECU's seem to be one of the few ECU's that rarely fail. If it comes down to the ECU you will have been dead unlucky. I would still go with connections or an anomaly in the cross valve control. Live data is the only way to go.
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birchy71
Active Member
I would also consider checking the abs sensors for resistance at the abs ecu can't qoute but when one of mine was knackered the dealer said the other 3 were all about 9 ohms and the knacked one was 300kohms , also does the suspension reset at all , just from whatyou've said I would lean towards the height sensors or their wiring. but yu might have to bite the bullet and get it on testbook somewhere.
Datatek
Well-Known Member
Auto ranging is a pain in the a#@e in this situation, if you have a fluctuating value the fecking things constantly try to swap range and it's impossible to make much sense of the readings.
sestorious
New Member
Saintv8 wen u say test resistance of height sensor where exactly do i connect wires too ? Birchy71 same with abs sensors where shall i connect wires to them ? Are the to the actual sensor or their wires? Cheers
