FINAL UPDATE 2/9/2026:
Great news, ECU repair is apparently not needed!
Removal and reconnect of the 3 ECUs resulted in no more clicking noise from footwell area under the glovebox. After multiple test drives and many system scans, there are zero Diagnostic Trouble Codes (faults). For what it's worth, of the 3 options listed near the bottom of this post, I had decided to send my ECUs out for analysis if the problems continued. Should the issue return, I will let you guys know in this post.
UPDATE 1/30/2026:
Regardless of which Module repair option I choose of the 3 listed below, I knew first I would need to remove the Modules and inspect wiring, connectors, and circuit boards.
So, I removed the Footwell Module, CAS Module, and Junction Box Electronics (JBE). Wow! These machines are engineered with some impressive fit and finish. The JBE and Junction Box fit perfectly on a tilting tray behind the firewall and in front of the airbag (all under the glovebox). The wiring harnesses, all connectors, and Modules looked great. No signs of any kind of damage or issues.
I decided to reinstall all 3 Modules and see if any changes come from it. Well, all of the clicking from the JBE area is gone, car runs perfectly from cold start to full temperature after 35 minutes of driving and testing most of the car's functions. I ran at least 10 diagnostic scans throughout the day and all worked perfectly with no Diagnostic Trouble Codes (faults). I plan on test driving it a few days a week for the next month to see if any problems reappear.
END:
Sharing my recent electrical issue.
Thoughts and suggestions are welcomed. Sorry for the long post but if you are interested, you won’t mind.
Had symptoms of poor battery while trying to start the vehicle (2012 E89 35i – original owner). I knew the battery was 6.5 years old and decided to start there. Charged it up using the contacts in the engine bay with no problem.
Problem seemed to go away but after a long drive same symptoms (clicking while trying to start and headlights acting strangely). Noticed relay switch clicking sounds coming from under the glove box. Assuming it is the JBE.
Bought a battery tester. Battery was in great condition and passed all tests including 14.8 Volts while engine was running.
Bought an affordable scanner/diagnostic tool. Found CAS errors A0A9, A0BE, A0BF, A0C0. CAS control fault and terminal 15 outputs 1-2 faults.
Cleared the faults many times and ran some of the reset options that are available on the diag tool. Car seemed to run normally for about a month.
Car sat for about 10 days. Started right up. No clicking from below the glove box. Drove 35 miles. Sat for 3 hours. Started up and after idling 30 seconds, shut off. Error on CID said to open/close door as there was some type of error/malfunction I don’t recall exactly what it showed. Tried to start it again and no problem. Drove 35 miles back home with no problem. Turned the car off and decided to try and restart car to see what would happen. Clicking and headlight symptoms returned.
Seems the CAS or JBE would be going bad. Especially after the engine/vehicle reach normal operating temperature. Seems like the problem becomes more frequent as the ECUs get warm from the normal amount of heat in the areas they occupy. So, I started the long multi-day journey on the web trying to decide next step and came up with 3.
Great news, ECU repair is apparently not needed!
Removal and reconnect of the 3 ECUs resulted in no more clicking noise from footwell area under the glovebox. After multiple test drives and many system scans, there are zero Diagnostic Trouble Codes (faults). For what it's worth, of the 3 options listed near the bottom of this post, I had decided to send my ECUs out for analysis if the problems continued. Should the issue return, I will let you guys know in this post.
UPDATE 1/30/2026:
Regardless of which Module repair option I choose of the 3 listed below, I knew first I would need to remove the Modules and inspect wiring, connectors, and circuit boards.
So, I removed the Footwell Module, CAS Module, and Junction Box Electronics (JBE). Wow! These machines are engineered with some impressive fit and finish. The JBE and Junction Box fit perfectly on a tilting tray behind the firewall and in front of the airbag (all under the glovebox). The wiring harnesses, all connectors, and Modules looked great. No signs of any kind of damage or issues.
I decided to reinstall all 3 Modules and see if any changes come from it. Well, all of the clicking from the JBE area is gone, car runs perfectly from cold start to full temperature after 35 minutes of driving and testing most of the car's functions. I ran at least 10 diagnostic scans throughout the day and all worked perfectly with no Diagnostic Trouble Codes (faults). I plan on test driving it a few days a week for the next month to see if any problems reappear.
END:
Sharing my recent electrical issue.
Thoughts and suggestions are welcomed. Sorry for the long post but if you are interested, you won’t mind.
Had symptoms of poor battery while trying to start the vehicle (2012 E89 35i – original owner). I knew the battery was 6.5 years old and decided to start there. Charged it up using the contacts in the engine bay with no problem.
Problem seemed to go away but after a long drive same symptoms (clicking while trying to start and headlights acting strangely). Noticed relay switch clicking sounds coming from under the glove box. Assuming it is the JBE.
Bought a battery tester. Battery was in great condition and passed all tests including 14.8 Volts while engine was running.
Bought an affordable scanner/diagnostic tool. Found CAS errors A0A9, A0BE, A0BF, A0C0. CAS control fault and terminal 15 outputs 1-2 faults.
Cleared the faults many times and ran some of the reset options that are available on the diag tool. Car seemed to run normally for about a month.
Car sat for about 10 days. Started right up. No clicking from below the glove box. Drove 35 miles. Sat for 3 hours. Started up and after idling 30 seconds, shut off. Error on CID said to open/close door as there was some type of error/malfunction I don’t recall exactly what it showed. Tried to start it again and no problem. Drove 35 miles back home with no problem. Turned the car off and decided to try and restart car to see what would happen. Clicking and headlight symptoms returned.
Seems the CAS or JBE would be going bad. Especially after the engine/vehicle reach normal operating temperature. Seems like the problem becomes more frequent as the ECUs get warm from the normal amount of heat in the areas they occupy. So, I started the long multi-day journey on the web trying to decide next step and came up with 3.
- Take to dealer or local BWM shop and probably spend thousands and hope all would be on the up and up. Or worse, get some kind of negative experience and never be sure what really was the situation. Probably relatively expensive and not very rewarding. Although, it is a great feeling to pay a local shop that does great and trustworthy service.
- Roll up my sleeves, remove the CAS and DME and send ECUs to a USA ECU repair shop. This certainly seems like a good option and the vendors seem very reputable from what I gathered.
- Use BMW AOS and TIS online subscription to get the various software like ISTA and others to diagnose/troubleshoot. Then, buy a new or used CAS or JBE and code it/them myself. I have none of the software or experience at this time. Probably the most expensive and most rewarding if it goes well.
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Scottish Borders