Car Dies at a stop
06-06-2021 | 02:54 PM
#1
Thread Starter
MBWorld Fanatic!
Joined: Sep 2009
Posts: 2,795
Likes: 386
From: Houston, TX
2014 E63 AMGs, 2015 F-150 Lariat, 2010 Porsche C4S
Car Dies at a stop
Hello,
Thought I'd post in other forums because I only got a few relies in the W212 forum. I have a stock 2014 E63s with about 60K miles on the clock. I've had random but continuing issues where the car dies at a stop. I have SDConnect with Xentry, and have pulled codes several times. The only thing the pops up is a B1F8D14, "The lower sensor of the rear switching module has a malfunction. There is a short circuit to ground or an open
circuit."
In an attempt to isolate, via Vediamo, the ECO Stop/Start function was permanently shut off because it first seemed as if the dying only happened when in ECO mode. Problem still exists. I know there is a "Relay Starter-Alternator Backup Battery" (A0009822023) that may be involved. A Google search of the code points to this site: Autologic Live: Electrical fault malfunction on Mercedes C-Class - autotechnician - servicing the independent workshop. Not sure it relates.
Any ideas of what might be causing this? Also anyone know what the "lower sensor of the rear switching module" is? Seems odd that the car doesn't throw a code when the car dies unexpectedly.
Thanks,
Joe
Thought I'd post in other forums because I only got a few relies in the W212 forum. I have a stock 2014 E63s with about 60K miles on the clock. I've had random but continuing issues where the car dies at a stop. I have SDConnect with Xentry, and have pulled codes several times. The only thing the pops up is a B1F8D14, "The lower sensor of the rear switching module has a malfunction. There is a short circuit to ground or an open
circuit."
In an attempt to isolate, via Vediamo, the ECO Stop/Start function was permanently shut off because it first seemed as if the dying only happened when in ECO mode. Problem still exists. I know there is a "Relay Starter-Alternator Backup Battery" (A0009822023) that may be involved. A Google search of the code points to this site: Autologic Live: Electrical fault malfunction on Mercedes C-Class - autotechnician - servicing the independent workshop. Not sure it relates.
Any ideas of what might be causing this? Also anyone know what the "lower sensor of the rear switching module" is? Seems odd that the car doesn't throw a code when the car dies unexpectedly.
Thanks,
Joe
06-09-2021 | 11:31 AM
#2
Super Member
Joined: Feb 2015
Posts: 687
Likes: 59
From: USA
09E350, 07E63, 13CLS63
It seems like replacing the stop/start relay is a good start. I know $250 for that relay is not cheap. Or you can have the dealer inspects it, I think it's easy for them to find out, then you can decide to have it done there or not, some dealers have free inspection.
06-10-2021 | 02:18 PM
#3
Thread Starter
MBWorld Fanatic!
Joined: Sep 2009
Posts: 2,795
Likes: 386
From: Houston, TX
2014 E63 AMGs, 2015 F-150 Lariat, 2010 Porsche C4S
I'm going to replace the plugs (MB OEM) and coils (Bosch) and we'll see if it makes a difference. We ran a diagnostic while engine was running, and there was one fault on cylinder 5 that then went away. After that all were good, along with fuel pressures to each side. I realize that doesn't tell the whole fuel story in each cylinder (injectors). So now I'm gonna poke around about how to diagnose. Since I now have my 4-Post lift installed, it's so much nicer to do maintenance! Brake fluid flush and tranny service next up.
As always thanks very much for your help!
Regards,
Joe
