Power steering warning
Thread Starter
Member
Joined: Oct 2017
Posts: 196
Likes: 13
2010 C63 AMG, 2015 GL450, 2018 GLS 550, 2021 GLS 450
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?
Out Of Control!!
Joined: Apr 2019
Posts: 11,993
Likes: 6,827
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
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".
Thread Starter
Member
Joined: Oct 2017
Posts: 196
Likes: 13
2010 C63 AMG, 2015 GL450, 2018 GLS 550, 2021 GLS 450
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.
Out Of Control!!
Joined: Apr 2019
Posts: 11,993
Likes: 6,827
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
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; Nov 5, 2022 at 12:09 PM.
Thread Starter
Member
Joined: Oct 2017
Posts: 196
Likes: 13
2010 C63 AMG, 2015 GL450, 2018 GLS 550, 2021 GLS 450
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.
Thread Starter
Member
Joined: Oct 2017
Posts: 196
Likes: 13
2010 C63 AMG, 2015 GL450, 2018 GLS 550, 2021 GLS 450
