Author Topic: Fault Code 12772: Rear Sensor Fault, Resistive  (Read 3924 times)

Jughead

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Fault Code 12772: Rear Sensor Fault, Resistive
« on: June 28, 2013, 10:55:29 AM »
Came across this fault on an '02 F650GS this morning.  ABS Light would also not go out as normal and speedo didn't work.


Traced the problem down to 2 very corroded plugs.  Firstly this one.


Located against the BMS unit under the seat.  This is the rear ABS/Speed sensor plug.
This cleared the resistive error but the abs light still remained on and the speedo still didn't work.

Then I found this plug.


It was completely green with corrosion.  Once cleaned, everything worked as normal.

I am however unsure what this plug is for.  According to the wiring diagram, the Black/Yellow wire has to do with the start relay/diode.  Wasn't going to cut the harness open to get an answer either.  Suffice to say it resolved the issue.

Ramplify

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Re: Fault Code 12772: Rear Sensor Fault, Resistive
« Reply #1 on: July 02, 2015, 05:28:49 AM »
12772: Rear sensor fault, resistive fault code for me too.

Had this error also, found the rear sensor was too tight and fixed. Still had the warning light on and saw this post, so checked both connections. made it work momentarily. Cleaned both and although no corrosion anywhere (dry climate), I found the smallest bit of play in the second connection in the post.

More importantly, the yellow black wire connector was at fault in my case, and although clean, it was just a little loose and so had the issue intermittently.

Thanks to this post that helped me find the real cause.

Jughead

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Re: Fault Code 12772: Rear Sensor Fault, Resistive
« Reply #2 on: July 02, 2015, 07:44:50 AM »
 ;)

WayneC

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Re: Fault Code 12772: Rear Sensor Fault, Resistive
« Reply #3 on: January 05, 2018, 10:07:36 AM »
The Yellow/Black wire is the wire from the starter button to the operating coil of the Starter Relay, the reason for the connector is for the Alarm/Immobiliser