Your specialist subject: the life and times of the FRM module ..aka Footwell module aka body controller

[B21]

The Yellow Peril is poorly….started her up yesterday to find almost nothing working bar the engine!…plugged the Protool code reader and inundated with errors..layed down in a dark room with several beers..for several hours..

Next day ..the instrument cluster and audio system had returned…still no drive, no mirrors, no lights, no indicators, no front windows etc etc

Plugged code reader and..most faults had disappeared… as had the FRM module ..aka body controller aka footwell module..plugged ISTA in and low Mr FRM is poorly as shown in red (the other reds are irrelevant as they belong to removed / replaced /defunct units )…

So my FRM has gone to the happy hunting grounds..hopefully £50 ish will have new life breathed onto it by the FRM Doctor !

No obvious physical faults or corrosion etc …

It is a known issue on E90 platforms..but..till yesterday..I’d never seen one fail…

First world issues..

The FRM connects many things including interior / exterior lights, front windows (rear windows are controlled by the JBE), mirrors and a myriad of interconnected issues caused by their demise..

The major issue is that over 30 different modules can talk to each other over one of three data buses that are used in the E89…

These 3 data buses are cross connected..

When something fails it can s**t on the data bus dragging everything else down.

 

[javis20]

Are you going to send it out for repair?

 

[The.Analyst]

Mine died after swapping batteries

£60 for a chap to re flash it

 

[B21]

Are you going to send it out for repair?

Yes several folks repair them..how badly damaged each repair costs I’m not sure…

These guys have quoted £45 for mine to be fixed without seeing it..although it seems physically perfect..

https://www.djwwautodiagnostics.co.uk/

So it’s in the post to them..

A new one is £350-£400 ish..plus needs programming ..

 

[javis20]

I previously researched this when my FRM module failed. It's not actually not an electrical problem, it's a firm ware problem. https://www.bimmerfest.com/threads/the-official-guide-to-resetting-a-short-circuit-fault-in-a-frm-module.866044/

 

[AnubisZed]

I've had mine repaired twice now, only takes around 20 minutes to sort it.
I'm still considering getting the equipment to do it myself.
Basically it's resetting a counter within the firmware.
I've gone one better, mainly as the guy that does mine is 30 miles away, and that is that i've bought a used FRM which has had the VIN changed in it and coded to the car and is now a spare if mine goes again.

They don't normally go in day-to-day use, it's normally a surge of some sort to does it. One way is leaving the key in the slot when disconnecting the battery, so when you reconnect the battery it surges the FRM and blows it, but there are numerous ways that'll do this.
£40 to £60 is a typical going rate to sort it.

 

[B21]

I previously researched this when my FRM module failed. It's not actually not an electrical problem, it's a firm ware problem. https://www.bimmerfest.com/threads/the-official-guide-to-resetting-a-short-circuit-fault-in-a-frm-module.866044/

That works for resetting the short circuit counters on the lights etc..BUT..AFAIK that won't work for a unit like mine that has gone off-line and you can't talk to it at all.. :tumbleweed:

 

[B21]

As a close out (hopefully)..the chap, 2 hours after receiving the FRM posted it back to me ..

Arrived next day..just fitted in a -4c garage..

All the wires and connectors stiff as hell…nice cuts to the hands as I tried cold weather gynaecological operations under the dash of the Z4.

2 huge and one big connector to wrestle into place ..a real bitch in cold weather…

Anyway ..it seems all things I’ve tried so far boot up…I’ll do a thorough check tomorrow