Omega Owners Forum
Chat Area => General Car Chat => Topic started by: Doctor Gollum on 01 November 2016, 11:02:42
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Using the very helpful guide here... http://www.bimmerforums.com/forum/showthread.php?1395944-HELP!-ASC-ABS-Problem-E39-523i
Suspicion fell towards the osf sensor as the gearbox is playing silly buggers in automode and not changing up to 4th or 5th... manually is fine. Speedo and cruise control also working as normal
I have dug out the multieter. For some reason, my meter registers the resistance on all four sensors as an overload, both forwards and backwards :-\
But, the diode readings are all between 1.941 and 1.974v and all OL in reverse. Also all four sensors also produce a voltage when the wheels are spun, increases with wheel speed.
From this, would it be reasonable to assume that the issue is most likely with the ECU itself?
Will pull the osf wheel in order to double check sensor is clean, just to rule it out...
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Right, wheel off... Sensor removed and cleaned, but looked ok :-\
(http://i1277.photobucket.com/albums/y486/05omegav6/Mobile%20Uploads/DSC_0287_zpsmi9mztbj.jpg)
Wiring checked between sensor plug and ecu plug and intact, diode voltage at sensor matched reading taken at ecu plug.
All back together and lights went out once the car moved. Gearbox back to normal too...
Osf wheel bearing needs doing sooner rather than later so it might be that with the slight play that the sensor 'lost sight' of the hub :-\
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Most sensor related failures I have seen have been wheel bearing or the reluctor rings failing/cracked.
Usually gives an incorrect signal code or similar, when viewing live data you get a lower speed on that corner.
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Reluctant rings on these are built into the bearing seal
... Will replace bearing before sending the ecu off ;)
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Lights are all back on again... >:( speedo, cruise and gearbox all working as normal...
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Have you read codes front ecu ?
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Lights are all back on again... >:( speedo, cruise and gearbox all working as normal...
Speed signal for rear wheel drive vehicles is usually derived from the rear wheels :y
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Have you read codes front ecu ?
That will be my next port of call, but don't have the facility.
Cruise and box now not working... Cruise and speedo come from either side rear, as per bimmerfest guide, nsf is steering yaw reference and osf is box...
Fault could lie with the steering column sensor as I get the airbag light on cold damp mornings, clears once car is warm.
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Is the E39 an OBD shaped port or the older round diag port under the bonnet?
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OBD port next to drivers cubby :y
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Is the E39 an OBD shaped port or the older round diag port under the bonnet?
I've seen a few with both :-X
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Is the E39 an OBD shaped port or the older round diag port under the bonnet?
I've seen a few with both :-X
Haven't noticed one in the engine bay :-\ but definitely one in the drivers cubby ;)
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If mine works you can always use it :y
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Al, I have the diagnostic lead and BMW INPA software that will do codes, live data, and actuator tests etc on all systems.
If you wish to borrow it just say the word :y
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Codes read, cleared and returned as soon as car moved...
Right Rear Wheel Sensor Speed Signal Implausible. Or words to that effect...
Have removed, cleaned and refitted sensor to no avail.
Would it be reasonable to assume that this sensor is toast?
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Swap left to right, see where fault goes?
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Most cars have very robust sensors, so I'd be thinking of reluctor ring, wiring or ecu
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Codes read, cleared and returned as soon as car moved...
Right Rear Wheel Sensor Speed Signal Implausible. Or words to that effect...
Have removed, cleaned and refitted sensor to no avail.
Would it be reasonable to assume that this sensor is toast?
Wheel bearing? Knackered toothed wheel? Dodgy wiring? Suspect ECU? Especially considering that it is likely to be a Bosch unit.
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Swap left to right, see where fault goes?
Good shout :y job for tomorrow...
Reluctor ring is built into bearing seal, wiring appears ok. Sensor might have taken a pounding when I was trying to separate the drive shaft from the hub... Took a fairly hefty pounding with a sledge hammer to free it off.
Bearing assembly and drive shaft are new on that side, although problem occurred a fortnight after bearing etc was fitted...
These are apparently prone to both sensor and ecu failure :-\
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By the sound of it you have damaged the magnetic ring in the bearing (looks and feels like fridge magnet material)
Had this on a subaru. two new bearing fitted by previous garage. Hooking up the sensors to a silly scope showed segments missing creating the fault.
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By the sound of it you have damaged the magnetic ring in the bearing (looks and feels like fridge magnet material)
Had this on a subaru. two new bearing fitted by previous garage. Hooking up the sensors to a silly scope showed segments missing creating the fault.
New bearing went straight in with no issues, they slot in place and are bolted up... fault occurred two weeks/800 miles after bearing change. Had it been damaged prior to fitting, surely the fault woud have been present from the get go :-\
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Brand new Bosch sensor fitted, reset the codes and job done, all working wot like it should :D
Took longer to type the post than to do 8)