|
Fred V
Regular
Date registered: Apr 2014
Location: Green Mnts
Vehicle(s): 02 G500
Posts: 88
| Normal voltages?
The G did fine through the cold weather but yesterday after work, when the temp was up in the high 20s, I got a "Battery/Alternator Visit Workshop" message. Drove home uneventfully but carefully. Checked the voltage at the battery and with the built in system that shows voltage on the dash screen. 12.4 to 12.6 with the car off, 13.8 with engine idling and the head lights on. Drove to work and back today with the voltage screen up on the dash which showed 13.9-14.0 the entire time. The "1 malfunction" message remains and the red warning screen comes up each time I start the engine. I have ordered a new voltage regulator but the voltage appears to be fine. The car is now just over 100k miles so I'm guessing I should change the voltage regulator just based on mileage.
Electronic glitch or was the voltage regulator/alternator giving me a heads up?
Does the red warning screen go out on its own or require some sort of reset?
Thank you. |
|
| |
|
petermerle
Expert
Date registered: Apr 2006
Location: Cape Town ( deep south )
Vehicle(s): W460 *1, W123 *2, W124
Posts: 1315
| Re: Normal voltages?
Check out battery first |
|
| |
|
Fred V
Regular
Date registered: Apr 2014
Location: Green Mnts
Vehicle(s): 02 G500
Posts: 88
| RE: Normal voltages?
I have driven around all week, essentially ignoring the warning.
I have been turning on the voltage in the dashboard display and have been keeping an eye on that each time I start the car and while driving. The voltages have remained as posted previously, ~12.4 with the car off, 13.8 with engine idling and the head lights on, 13.9-14.0 while driving.
To display voltage on the dashboard display; close doors, insert key in ignition, turn one click. Use the toggle buttons on the steering wheel to change the warning screen back to the normal display. Now press the reset button rapidly three times. Display will show voltage but since you have not yet started the car the voltage is that of the battery. When you start the car the voltage should now show what the alternator is doing. You can drive around with the voltage being displayed or use the toggle buttons in the steering wheel to show standard display screens. When you turn the car off and back on again the display rests to standard, not showing voltage.
The warning is an error. But, I am still going to replace the voltage regulator as a precaution, as far as I know it is an original 2002 part. |
|
| |
|
J.R.
Elite Veteran
Date registered: Apr 2006
Location: Southern Maryland
Vehicle(s): 00 G500, 09 911 4S, 11 Cayenne S, 86 280GE (sold)
Posts: 828
| RE: Normal voltages?
How old is the battery? It might be worth a loads test at your local parts store before swapping out a VR. The new testers are pretty good and I think they can test in situ and provide some alternator VR health too.
|
|
| |
|
Fred V
Regular
Date registered: Apr 2014
Location: Green Mnts
Vehicle(s): 02 G500
Posts: 88
| RE: Follow up.
Thank you all. I drove with the voltage display on for a few weeks after the replacement of the voltage regulator. Voltage ran 14.0 to 14.1 with headlights on, nothing else on (no stereo, no fan, etc.). Still had the warning light and had a slow drop in battery voltage with time (checking just prior to starting engine). Would bounce back up with driving but then trend down, 12V after sitting for a day. Changed battery, had a 2yr old Napa, now new AGM. The warning light did go off. Voltage as I drive around remains the same, 14.0 to 14.1. |
|
| |
|
WEBIII
Extreme Veteran
Date registered: Oct 2010
Location: Inlet Beach, FL
Vehicle(s): 461.318, 463.241
Posts: 315
| Re: Normal voltages?
I used to buy Napa batteries and they would last about 2 years. |
|
| |
|
gbenzer
Extreme Veteran
Date registered: Dec 2006
Location: Georgia
Vehicle(s): 2007 G-500, 2017 Audi Q7
Posts: 418
| RE: Normal voltages?
I have a 2007 G 500. Is it possible to replace the voltage regulator only or is it integral with the alternator thus requiring replacement of both the alternator and voltage regulator as a unit? |
|
| |
|
AlanMcR
Expert
Date registered: Apr 2006
Location: US, CA, Los Altos
Vehicle(s): G300DT E300DT 230SL
Posts: 3500
| RE: Normal voltages?
gbenzer - 2/11/2018 7:38 PM I have a 2007 G 500. Is it possible to replace the voltage regulator only or is it integral with the alternator thus requiring replacement of both the alternator and voltage regulator as a unit? The regulator is a replaceable sub-unit on every MB alternator I've ever opened. What wears out is the two carbon brushes. After about three changes of the brushes the copper rings that they slide on are also worn out. Changing those is a much bigger deal.
|
|
| |
|
Rangek1d
Member
Date registered: Feb 2018
Location: Calgary, Canada
Vehicle(s): 03 G55 Brilliant Silver
Posts: 25
| Re: Normal voltages?
I've noticed something similar:
Engine OFF: UB: 12.0v
Engine ON: UB: 14.3v
Engine ON: UB: 14.1v (Command Unit and Headlights ON)
Is this normal or new battery? I noticed a slight loss in radio signal for a brief second when I turned the front windshield heater on, I assume also power related? |
|
| |
|
NHDave
Extreme Veteran
Date registered: Dec 2013
Location: Seacoast NH.
Vehicle(s): 2004 AMG
Posts: 464
| Re: Normal voltages?
Battery should be 12.4V or better at rest. I would say..new battery. |
|
| |
|
Rangek1d
Member
Date registered: Feb 2018
Location: Calgary, Canada
Vehicle(s): 03 G55 Brilliant Silver
Posts: 25
| Re: Normal voltages?
NHDave - 2/16/2018 5:35 AM
Battery should be 12.4V or better at rest. I would say..new battery.
Oh okay, that's what I've been reading around as well. I just don't understand why it starts up so quick. A failing battery wouldn't start up as fast as mine does. Flick of the wrist and the G turns on, no questions, no hassle unless it's very cold then it'll take a second. |
|
| |
|
NHDave
Extreme Veteran
Date registered: Dec 2013
Location: Seacoast NH.
Vehicle(s): 2004 AMG
Posts: 464
| Re: Normal voltages?
A few years ago..I've experienced the same issue..like you, truck always started right up! And it should because there's still 12V to turn the starter. This is not about a dead battery but a battery that can't hold it's intended targeted charge any longer or a voltage regulator that isn't doing it's job. Unlike cars from the past.."were you might start the engine with the slightest amount of battery voltage" not so with todays cars and electronics. The ECU relies on the batterie's constant mid 12V supply after start up and the battery is maintained by a trickle charge from the alternator. If the battery can't hold the intended voltage or isn't getting a charge from the alternator..voltage declines and with it, the electronic gremlins appear in greater numbers! With the engine running, the alternator's 14V handles all the conveniences with a reserve for trickle charging. With all I've read from good folks..here and there, I'll guess it's a fine line between .2 .4V that decides a batteries fate!
Edited by NHDave 2/21/2018 9:04 AM
|
|
| |
|
Rangek1d
Member
Date registered: Feb 2018
Location: Calgary, Canada
Vehicle(s): 03 G55 Brilliant Silver
Posts: 25
| Re: Normal voltages?
So would you say new battery or regulator? Or both? |
|
| |
