Intermitent SBCH and Phone ......

[Bryan Allman]

My 04 W211 E55 has a habit of turning off features on a regular basis. Typically this revolves around the SBC Hold feature - which works perfectly for weeks, then for some reason just beeps and is no longer available.

At the same time, my phone ceases to be recognised and displays the message 'No Phone'.

I have also noticed that the 'death' of these features also seems to coincide with a 'reset' on the SatNav - where the screen shows an egg timer for some minutes before SatNav engages.

I have had both batteries checked and recharged, though I still get the message re Battery Protection after three days of none use.

All fuses are OK and no other functions seem to be effected.

Before I recognised the connection between all three events, I had managed to get the phone working again by disconnecting the Nokia unit in the boot for about 20 minutes after which it would work OK. This time, no reset.

So .......... any ideas ?

Is there actually any relationship between the three features (particularly SBC Hold), or is it pure fluke that they fail together?

Could it just be the phone unit putting a spike through the system ?

Or is it a typical 04 W211 electrickery issue ?

All comments appreciated

 

[AndyPCD]

The sbch problem is sometimes caused by a faulty selector module there is a microswitch inside it that is prone to failing and this can cause the fault you describe.

With the satnav reset and phone issue it sounds like a control unit on the optical ring is shutting down and resetting itself.

With the battery i have had this fault before and had batteries checked and the come up ok but still replaced the battery in the boot and it is fine after that. What is the post date on the battery.

But to confirm all of these it would be best to stick it on a star machine and get the faults read

 

[mr. shr]

Reference the SBC-H function, I concour with the faulty selector module as my S211 has the same fault and STAR revealed the selector module as being at fault. (Every possibility yours is the same, but must use STAR to confirm).
I've been told a new module is required (about 450 pounds just for the part apparently).

Unless anyone know if existing part can be fixed?