Power steering warning
11-02-2022, 08:31 AM
#1
Member
Thread Starter
Power steering warning
Hello All again,
I am getting a power steering warning that flashes for a moment and then disappears. Steering doesn’t tight or anything and it’s very brief. Additionally Presafe inoperative will come up and stay up randomly until
power cycled. Based on my experience with my C63 I’m guessing this is a battery issue.
Is it best practice to replace both batteries or just the Auxiliary?
I am getting a power steering warning that flashes for a moment and then disappears. Steering doesn’t tight or anything and it’s very brief. Additionally Presafe inoperative will come up and stay up randomly until
power cycled. Based on my experience with my C63 I’m guessing this is a battery issue.
Is it best practice to replace both batteries or just the Auxiliary?
11-02-2022, 11:38 AM
#2
MBWorld Fanatic!
Join Date: Apr 2019
Location: Silicon Valley
Posts: 5,036
Received 3,151 Likes
on
2,090 Posts
MY'14 W212 M276 3.5NA @55kMi
many options to deal with cause
These warnings are about MAIN power glitching, not the small AUX. You can use a scanner to read what codes and modules are getting disrupted.
Check the date code on top the main battery or better get the battery load tested to assess need for its replacement.
Chances are the charging system is faulty and causing deep drain on long drives. You may pop the Voltage/Amp display from the in-dash "Maintenance menu".
Check the date code on top the main battery or better get the battery load tested to assess need for its replacement.
Chances are the charging system is faulty and causing deep drain on long drives. You may pop the Voltage/Amp display from the in-dash "Maintenance menu".
11-03-2022, 04:19 PM
#3
Member
Thread Starter
These warnings are about MAIN power glitching, not the small AUX. You can use a scanner to read what codes and modules are getting disrupted.
Check the date code on top the main battery or better get the battery load tested to assess need for its replacement.
Chances are the charging system is faulty and causing deep drain on long drives. You may pop the Voltage/Amp display from the in-dash "Maintenance menu".
Check the date code on top the main battery or better get the battery load tested to assess need for its replacement.
Chances are the charging system is faulty and causing deep drain on long drives. You may pop the Voltage/Amp display from the in-dash "Maintenance menu".
UB 14.6V-11.5
It starts at Just under IB 3.8
falls to under 2IB after about 5minutes. No lights
I’m going to check the battery later, I pulled the cap off and it’s an MB OEM with no record of replacement
im guessing maybe Alternator/VR, but honestly since I’m already there I’ll probably just replacement both.
11-05-2022, 12:04 PM
#4
MBWorld Fanatic!
Join Date: Apr 2019
Location: Silicon Valley
Posts: 5,036
Received 3,151 Likes
on
2,090 Posts
MY'14 W212 M276 3.5NA @55kMi
good + bad...
The IB current displayed around 3Amps says the battery is already pretty well charged near full. That is good news. 
(20A,... 30A, 50A, 90A would be discharged).
The voltage range you report from 14.5V to 11.5V does show a problem.
Anytime the running voltage swings below 12.3V it's bad news onboard.
Try to figure when this low-voltage condition happens during every drive cycles... towards the end right?
These cars do use a Voltage-Regulator built inside the alternator as you'd expect but it is remote controlled externally through a serial data link. Meaning VR acting crazy is very likely caused externally, ie. VR is A-ok.
A great many factors can disrupt the 12.6V regulation while keeping the 14.5V regulation perfect. This' the magic of Mb and why we like 'em: they keep us guessing what mood they are in.
(20A,... 30A, 50A, 90A would be discharged). The voltage range you report from 14.5V to 11.5V does show a problem.
Anytime the running voltage swings below 12.3V it's bad news onboard.
Try to figure when this low-voltage condition happens during every drive cycles... towards the end right?
These cars do use a Voltage-Regulator built inside the alternator as you'd expect but it is remote controlled externally through a serial data link. Meaning VR acting crazy is very likely caused externally, ie. VR is A-ok.
A great many factors can disrupt the 12.6V regulation while keeping the 14.5V regulation perfect. This' the magic of Mb and why we like 'em: they keep us guessing what mood they are in.
Last edited by CaliBenzDriver; 11-05-2022 at 12:09 PM.
11-05-2022, 02:27 PM
#5
Member
Thread Starter
The IB current displayed around 3Amps says the battery is already pretty well charged near full. That is good news. (20A,... 30A, 50A, 90A would be discharged).
The voltage range you report from 14.5V to 11.5V does show a problem.
Anytime the running voltage swings below 12.3V it's bad news onboard.
Try to figure when this low-voltage condition happens during every drive cycles... towards the end right?
These cars do use a Voltage-Regulator built inside the alternator as you'd expect but it is remote controlled externally through a serial data link. Meaning VR acting crazy is very likely caused externally, ie. VR is A-ok.
A great many factors can disrupt the 12.6V regulation while keeping the 14.5V regulation perfect. This' the magic of Mb and why we like 'em: they keep us guessing what mood they are in.
(20A,... 30A, 50A, 90A would be discharged).The voltage range you report from 14.5V to 11.5V does show a problem.
Anytime the running voltage swings below 12.3V it's bad news onboard.
Try to figure when this low-voltage condition happens during every drive cycles... towards the end right?
These cars do use a Voltage-Regulator built inside the alternator as you'd expect but it is remote controlled externally through a serial data link. Meaning VR acting crazy is very likely caused externally, ie. VR is A-ok.
A great many factors can disrupt the 12.6V regulation while keeping the 14.5V regulation perfect. This' the magic of Mb and why we like 'em: they keep us guessing what mood they are in.
11-05-2022, 03:48 PM
#6
MBWorld Fanatic!
Join Date: Apr 2019
Location: Silicon Valley
Posts: 5,036
Received 3,151 Likes
on
2,090 Posts
MY'14 W212 M276 3.5NA @55kMi
displayed message
the front radar sensors are pretty sensitive to voltage swings but not the source of trouble. They do like to get reset.
11-05-2022, 05:28 PM
#7
Member
Thread Starter
