[imidazol97]

Does the auxiliary battery handle the load of the 4 circuits on the Battery Control Module during the entire stop cycle or does it only handle the load of those ancillary items while the engine cranking is occurring? If it's only during the starter cranking, that's a short time.

My thinking is that the switching between batteries occurs in the Battery Control Module. Has anyone opened the box part of that module? Is it mechanical with relays when a contact that's rough could not make contact at first when the circuit with the radio is powered back up on the AGM main battery?

I think if my battery were 5 years old (mine in my Mallibu is approaching 6 years so I'm following the battery experiences closely and getting ready to replace mine if needed), I'd replace the AGM main battery just in case there's something going wrong with it. If you're losing a year of use of it, that's a small cost on a per year basis vs the certainty of having a new, good battery in place. Makes troubleshooting elsewhere easier.

IS anything else on the circuit from the Battery Control Module that the radio is on?
Does anyone have a circuit diagram of the power for the radio unit that includes the Battery Control Module?

 

[repairman54]

 

[SmallTownDave]

Essentially make sure all connections are tight then replace control module?

 

[SmallTownDave]

I get the control module Friday or Saturday, I'm planning the next step if that doesn't work.

It worked!!!

Thank you all for the help I couldn't have figured it out without this forum.

 

[Ampx]

It worked!!!

Thank you all for the help I couldn't have figured it out without this forum.

Wait.... what worked?! I’m having the same issue.

 

[Jrondini]

I get the control module Friday or Saturday, I'm planning the next step if that doesn't work.

Did the control module fix the issue?

 

[CG215]

It worked!!!

Thank you all for the help I couldn't have figured it out without this forum.

What worked???? I'm having the same issue

 

[DrivenDaily]

Essentially make sure all connections are tight then replace control module?

Wait.... what worked?! I’m having the same issue.

Did the control module fix the issue?

What worked???? I'm having the same issue

Although he hasn't shared whether the control module was part of the fix, it appears that he's alluding to the info shared by @repairman54: clean up and tighten the grounds.

 

[s.thomas13190]

What worked???? I'm having the same issue

Ok. Just had a customer with the same issue. Code p305f both batteries are new. Radio shut off once the vehicle restarted on start/stop. The fix is the 175 amp mega fuse that’s located on the fuse block above the positive terminal of the main battery. Replaced fuse for $7 dollars and problem is solved.

 

[Moonwink]

Updated PIC6114B

 

[Jaquelpaige]

The battery in the trunk needs to be replaced. I just had mine replaced last month. The radio would cut off every time the start/stop would come on while I would be at the red light. I had auto zone put the test machine on it, and it showed low power, but I didn't know where. The check engine light wouldn't go off neither. I took it to a shop, and I showed the mechanic the print out i got from auto zone, and asked him what it meant. He said it was my small battery in the trunk. Now I went to another shop before him, and they said they would have to put it on their diagnostic machine for a few hours, and it's $175 just to look at it, and another $280 to hook it up on the machine. So they pretty much was going to try and take advantage of a female. But they had the wrong female. So the other guy knew just by looking at the paper I had, he put it on his machine for $75, and it confirmed that's what it was. He called and ordered it for $140, put it on, charged me only $215. My Mali doesn't cutoff anymore when the start/stop comes on at stops, and the check engine light went off.

 

[campb292]

Reminder to owners: a problem doesn't always have the same fix. The fix for Auto Stop issues in gen8 is generally a mix of main battery, aux battery, and DBCM/fuse block on the positive terminal. In this very discussion there are multiple fixes. Just like knocks in the rear suspension aren't always shocks.

In post 11, an owner replaces the aux battery attempting to resolve a radio cut out. It didn't fix the issue so they went ahead and replaced the main battery too. That fixed the problem.
In post 14 and 24, SmallTownDave checks and tightens all grounds he could find with no change. It was after replacing the DBCM/positive fuse block the problem was resolved.
In post 29, a mechanic replaces just the 175 amp fuse on the DBCM/fuse block and the problem is resolved.
In post 31, an owner replaced just the aux battery and it fixed the radio cut out issue.