D3 replaced fr speed sensor, deleted connector; still get fault C1A9478

[southernron]

N.B. I first posted over on disco3.co.uk, ref. DISCO3.CO.UK - View topic - Front Right Speed Sensor — C1A9478 (https://www.disco3.co.uk/forum/post2395440.html#2395440)

Front Right Speed Sensor — C1A9478
https://www.disco3.co.uk/forum/templates/vbnew/images/icon_report.gif (https://www.disco3.co.uk/forum/report.php?p=2395440)


I should of been clearer in my intiial post, but there are other fault codes (listed above, please ignore the long term gremlins fan speed high / egr yada yada).


What I first had was the christmas tree popup on dash. I initially missed the C1A94-78 code, and only saw 'vehicle speed sensor' related (catchall code I believe). So from there:

I monitored all four speed sensors while driving
They all work fine for an indeterminate time (fairly short, usually), then only the front right drops out, and it's christmas in July
I ordered and replaced new fr speed sensor, problem persisted
I reinstalled the old sensor which seemed fine after a clean, and spliced the wiring (replaced connector), Problem persisted.



With the above in mind, given I do have other fault codes, could it possibly be an earth issue? My thinking was all the other fault codes were cascade effects from the failing front right speed sensor.

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C1A9478
Right Front Wheel Speed Sensor


Incorrect signal alignment




Incorrect air gap of the sensor



Check the installation of the wheel speed sensor. Refer to the appropriate section in the workshop manual. Refer to the guided diagnostic routine for this code on the approved diagnostic system.
[/list]


Note; ABS Earth Point
I have not yet been able to test the ABS Earth point / ground — I believe it is the inner wheel arch drivers side earth, but I am not 100% sure.

I tried a lot of searching, but not 100% sure which is the ABS Module earth.

Ref. https://www.disco3.co.uk/forum/speed-senso...ight=C1a94 (https://www.disco3.co.uk/forum/speed-sensor-wires-126371.html?highlight=C1a94)
https://www.disco3.co.uk/gallery/albums/us..._C0517.pdf (https://www.disco3.co.uk/gallery/albums/userpics/32286/227_C0517.pdf)
Anti-lock braking system: Dtc trouble code index (Discovery 3, 2004-2009) - LRman.ru (https://www.lrman.ru/en/discovery/3/chassis/abs/pointer_to_dtc)
https://www.disco3.co.uk/forum/post2186193.html

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Full list of codes from last test drive
https://www.disco3.co.uk/forum/templates/vbnew/images/icon_report.gif (https://www.disco3.co.uk/forum/report.php?p=2395492)




U0400(68): Invalid data received (event diagnostic trouble code). Communication/data error, often a symptom of another issue.



U0416(86): Invalid data received from vehicle dynamics control module. Linked to suspension, ABS, or steering angle sensor issues.



U0122(87): Lost communication with vehicle dynamics control module (VDCM/ABS module). CAN bus communication problem, sometimes intermittent.



C1A94(78): Right front wheel speed sensor – incorrect signal alignment or air gap. Usually a mechanical issue (bearing, reluctor ring, or sensor alignment).



U0416(94): Invalid data received from vehicle dynamics control module. Linked to suspension, ABS, or steering angle sensor issues.



P0500(00): Vehicle speed sensor (VSS) circuit malfunction. Often caused by ABS faults or wiring issues.



P0495(00): Engine coolant blower motor speed – high. Cooling fan running at higher than expected speed.



P140A(00): EGR sensor B – circuit range/performance. Relates to exhaust gas recirculation system sensor performance.

[Graeme]

If you haven't already done so, I suggest that the sensor be removed then compressed air blast into the hole as the driveshaft/wheel is slowly turned more than a full revolution in case foreign matter is trapped.