SL/R230: B1132 CAN communication fault with BNS, start battery not charging
06-16-2017, 03:03 PM
#1
Junior Member
Thread Starter
B1132 CAN communication fault with BNS, start battery not charging
I am looking at a 2004 SL600.
I car sat for a while and the starter battery died. Accessory battery is new, so it was on the low side but fine. I have an iCarSoft MBII reader that can read mercedes codes, and reset the "Battery- Visit Workshop" light (I do not recall the specific code it threw, but it went away and did not return after jumpstarting the vehicle). I replaced the battery and used a portable tender to keep 12v to the system while pulling the battery.
I got the new battery in and got the "Battery- Visit Workshop" light back on, only this time I can no longer connect to the BNS DTC. The only code I can read is from the instument/cluster DTC and it reads:
B1132-- Fault in CAN communication with control unit BNS
Status: Current and Stored
Car starts and runs with the Visit Workshop light, but now the front start battery is no longer geting 14v. The rear accessory battery is getting 14v.
Any ideas what is causing this?
I car sat for a while and the starter battery died. Accessory battery is new, so it was on the low side but fine. I have an iCarSoft MBII reader that can read mercedes codes, and reset the "Battery- Visit Workshop" light (I do not recall the specific code it threw, but it went away and did not return after jumpstarting the vehicle). I replaced the battery and used a portable tender to keep 12v to the system while pulling the battery.
I got the new battery in and got the "Battery- Visit Workshop" light back on, only this time I can no longer connect to the BNS DTC. The only code I can read is from the instument/cluster DTC and it reads:
B1132-- Fault in CAN communication with control unit BNS
Status: Current and Stored
Car starts and runs with the Visit Workshop light, but now the front start battery is no longer geting 14v. The rear accessory battery is getting 14v.
Any ideas what is causing this?
06-16-2017, 05:36 PM
#2
Junior Member
Thread Starter
I found this as a resource, I am still getting through the training pdf that is attached a few posts in. Still trying to figure it out
https://mbworld.org/forums/sl-class-...ol-module.html
https://mbworld.org/forums/sl-class-...ol-module.html
05-13-2024, 05:05 PM
#3
Junior Member
Join Date: Feb 2009
Location: CT, USA
Posts: 34
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3 Posts
2005 E500, 2004 SL600
I am looking at a 2004 SL600.
I car sat for a while and the starter battery died. Accessory battery is new, so it was on the low side but fine. I have an iCarSoft MBII reader that can read mercedes codes, and reset the "Battery- Visit Workshop" light (I do not recall the specific code it threw, but it went away and did not return after jumpstarting the vehicle). I replaced the battery and used a portable tender to keep 12v to the system while pulling the battery.
I got the new battery in and got the "Battery- Visit Workshop" light back on, only this time I can no longer connect to the BNS DTC. The only code I can read is from the instument/cluster DTC and it reads:
B1132-- Fault in CAN communication with control unit BNS
Status: Current and Stored
Car starts and runs with the Visit Workshop light, but now the front start battery is no longer geting 14v. The rear accessory battery is getting 14v.
Any ideas what is causing this?
I car sat for a while and the starter battery died. Accessory battery is new, so it was on the low side but fine. I have an iCarSoft MBII reader that can read mercedes codes, and reset the "Battery- Visit Workshop" light (I do not recall the specific code it threw, but it went away and did not return after jumpstarting the vehicle). I replaced the battery and used a portable tender to keep 12v to the system while pulling the battery.
I got the new battery in and got the "Battery- Visit Workshop" light back on, only this time I can no longer connect to the BNS DTC. The only code I can read is from the instument/cluster DTC and it reads:
B1132-- Fault in CAN communication with control unit BNS
Status: Current and Stored
Car starts and runs with the Visit Workshop light, but now the front start battery is no longer geting 14v. The rear accessory battery is getting 14v.
Any ideas what is causing this?
05-13-2024, 05:15 PM
#4
Junior Member
It sounds like your BCM (Battery Control Module) aka BNS, has failed. There are many threads about this. You're going to have to physically access the BCM and open it up and take a look at it. There are threads that show what damaged modules look like.
Be careful, connectors 30 and 30a both connect to large lead acid batteries and will do a lot of damage if you short one of them out! Follow the MB instructions about disconnecting both batteries before you start messing around with the BCM.
Be careful, connectors 30 and 30a both connect to large lead acid batteries and will do a lot of damage if you short one of them out! Follow the MB instructions about disconnecting both batteries before you start messing around with the BCM.
05-16-2024, 09:35 AM
#6
MBWorld Fanatic!
That looks good, but you could still have a fault with the module. However, I would exhaust every other avenue first before you drop $2k on a used module. You need to read your own codes and see what the stored and current faults are. Even though the symptoms are the same, your problem might be totally different.
