2004 R1200GS High rear brake pressure fault code 24972 !

[Finny]

I am sure there has been lots of discussion on this topic. Have done some research but am looking for guidance and direction for this newbie. Residual braking on rear(front is fine) with warning lights going off there head. This issue was intermittent (say 50miles or 85 kms into a ride before it lost the rears. Had a BMW dealer bleed the ABS and now is constant. Advice was replace the unit at A$3000  I would like to exhaust all other possible options before going down this track. Cheers Finny

[Jughead]

I am sure there has been lots of discussion on this topic. Have done some research but am looking for guidance and direction for this newbie. Residual braking on rear(front is fine) with warning lights going off there head. This issue was intermittent (say 50miles or 85 kms into a ride before it lost the rears. Had a BMW dealer bleed the ABS and now is constant. Advice was replace the unit at A$3000  I would like to exhaust all other possible options before going down this track. Cheers Finny

One of the pressure sensors has failed.  There are 4 altogether, being front control, front wheel, rear control and rear wheel.

Your error lies on one of the rear circuits, but the error code should tell you whether it is the control or wheel circuit that is faulty.

Sensor looks like this:

[Finny]

Thanks Jughead for your response. Just ran the test again and the fault code reads 24972 Pressure in rear wheel circuit to high. The sensor looks quite involved and where have you opened up to expose it ? Sounds bad to me. Paul

[Jughead]

Am busy with a pump as we speak.  Took this little screen clip that may interest you.

Note the 4 pressure circuits.

Pressure in front control circuit is monitored and the values change accordingly.
Pressure in rear control circuit is monitored and the values change accordingly.
Pressure in front wheel circuit is monitored and the values change accordingly.
Pressure in rear wheel circuit is monitored but the value does not change and is stuck on 127.20 Bar.

This pump initially gave me errors front and rear.  I have replaced just the front sensor and that is now working 100%.  Now to strip it again and do the rear.

https://youtu.be/1I_k5fMcNWE

[Finny]

Really appreciate your input as I think I may have similar issues.
                                                                           Staionary Test         Front brake applied       Rear brake applied
Pressure in front wheel control circuit                                   18                     47
Pressure in rear wheel control circuit.                                   18                                                      40
Pressure in front wheel wheel circuit                                     19                     28
Pressure in rear wheel wheel circuit                                     101                                                    101
I found a post by you showing how to remove and check the sensors for sticking in the ABS unit which may be my issue.
I might let you work through your current unit and see how that goes.
Cheers Paul

[Jughead]

Have now replaced the rear sensor as well and properly bled the system.  Herewith the new values.  ABS is now 100% functional.

https://youtu.be/KCijAPJbwGo

[Finny]

Great work so you suggest its worth checking and or replacing the rear sensor ? Can you source replacement sensors ? it seems my fault is similar to the unit you have serviced. Paul

[Jughead]

Great work so you suggest its worth checking and or replacing the rear sensor ? Can you source replacement sensors ? it seems my fault is similar to the unit you have serviced. Paul

Some micro surgery involved in replacing only one sensor.  Individual sensors are impossible to get hold of.  Have been trying for over a year to source them.

Will have to replace the entire unit with both sensors.  Even those are VERY hard to come by and I usually source any second hand pumps I can find to salvage useful parts.

[Finny]

Thanks so second hand pump will be the go. So checking the pressure relief valve  and bleeding would be a waste of time from your experience ? Cheers Paul

[Jughead]

Thanks so second hand pump will be the go. So checking the pressure relief valve  and bleeding would be a waste of time from your experience ? Cheers Paul

Afraid so.