'99 e300d - alarm issue? - PeachParts Mercedes-Benz Forum

notfarnow · #1 09-09-2008, 08:20 AM

First off, let me know if this should be posted in the "tech help" section. It's not a diesel-specific issue, but last time I posted about an AC issue, they sent me to the diesel side.

Here's the scoop:

1) Last night my wife parked the car, locked the doors. About 15 minutes later I walked to the car and noticeed the fogs and side lamps were flashing on & off. I figured she must've hit the "panic" button, but wouldn't the alarm have gone off? She insists she didn't do anything, but she's brought cars home without bumpers and said that.

2) Then this morning, when I locked the car the alarm turned on. Unlocked the car, alarm turned off. Tried the "emergency" mechanical key... same thing. Alarm turned on went the car was locked, turned off when I unlocked it. Unsure of what to do, I got in the car, started it, turned it off and tried locking it again. This time, the alarm didn't come on.

Anyone hear of this before? Is there something simple that causes this? Is there something complicated that causes this? Is my car haunted?

KarTek · #2 09-09-2008, 08:26 AM

Quote:

Originally Posted by notfarnow

She insists she didn't do anything, but she's brought cars home without bumpers and said that.

Quote of the day!

Sorry, I can't help with the alarm question...

TMAllison · #3 09-09-2008, 01:33 PM

I'd monitor batt voltage at the CCU while driving. Press and hold rest for 5 secs. Toggle using AUTO button to creen 24. May be low?

notfarnow · #4 09-09-2008, 01:36 PM

Funny you mention that. A couple times in the past month or so, when I turn the car off I get the "low battery" warning. I was planning on getting a new one before it gets cold out... maybe that is the cause?

Just so I can follow, why would a low battery trigger these issues?

TMAllison · #5 09-09-2008, 01:59 PM

Was a hunch. Low batt voltage causes issues with other ssytems too as they are all monitored electronically. Lots of ABS/BAS lights etc. Usually has to do with the sensors not receiving enough power to "report" back triggering a light.

notfarnow · #6 09-09-2008, 02:13 PM

Well thanks, I appreciate it. I am used to working on "old school" very mechanical systems that you can figure out by looking at them. I don't have enough experience with these cars to get "hunches" yet.

I will monitor the battery voltage... thanks again for the lead!

notfarnow · #7 09-12-2008, 05:34 PM

Quote:

Originally Posted by TMAllison

I'd monitor batt voltage at the CCU while driving. Press and hold rest for 5 secs. Toggle using AUTO button to creen 24. May be low?

I'm running between 12.8-13.2

I assume I should be getting a steady 14+?

I'll check grounds, etc, and check the output right at the alternator.

Is there a brush kit available for this alternator, or will I have to swap the whole unit?

TMAllison · #8 09-12-2008, 06:00 PM

Mine usually runs mid 13's. May get down in the 12's with AC on at idle. Prob more important is voltage prior to/or while starting and immediately thereafter.

The reg is available separately, don't know about brushes.

notfarnow · #9 09-12-2008, 06:33 PM

Quote:

Originally Posted by TMAllison

Mine usually runs mid 13's. May get down in the 12's with AC on at idle. Prob more important is voltage prior to/or while starting and immediately thereafter.

The reg is available separately, don't know about brushes.

I just tested with a multimeter.

With the car idling, I'm getting a steady 13.8 from ground to the positive hookup near the brake booster. Same 13.8 measured across the battery.

With the car off, I have 11.1 volts.

Cranks S L O W and dipped to 8.2 (on the display) while cranking

Methinks the battery is pooched

TMAllison · #10 09-12-2008, 06:44 PM

The 11.1 doesnt look good and will be get worse when it gets colder.

notfarnow · #11 09-12-2008, 06:47 PM

well the slow cranking just started creeping up in the last day or two... so it's going downhill fast. I'm not going to wait: I'll see what I can grab for a battery in the AM.

Thanks again for all your help!

notfarnow · #12 09-16-2008, 12:24 PM

The dealership wanted $265 for a battery with 650 CCA and a 100minute reserve.

I shopped around, and found one at Canadian Tire with 850 CCA and a 120 minute reserve. Direct fit for $152 after taxes, including a $9 add-on 9 year warrantee.

Starts like a champ now!

One thing I noticed is that the CCU readout for Voltage (#24) reads exatly 1 volt lower than what I'm getting with my multimeter. I tried another multimeter, same thing. Can anyone confirm that they get the same?

nhdoc · #13 09-16-2008, 12:44 PM

Quote:

Originally Posted by notfarnow

The dealership wanted $265 for a battery with 650 CCA and a 100minute reserve.

That is nuts...I just replaced the battery in mine a couple of weeks ago and the M-B battery was $114.75 at the dealer's parts counter. I think your dealer is hosing you.

Apparently M-B sells a Gel-Cell that is more than twice the price of the standard Silver-Calcium Lead Acid battery but there is no reason why they should not have offered you the less costly one (unless there is something special about the battery market in Canada which requires gel-cells?).

miker300d · #14 09-16-2008, 03:29 PM

Check if the central locking pump is getting water in it. The pump should be under the rear seat on the passenger side. Water can follow the wires down into the connector and short it out. This water leak is not always noticeable without the seat out of the way. remove and inspect all 3 connectors and see if they are growing green. The alarm horn can cause similar problems, it is located at rear of rf wheel behind the fender liner. Make sure the alarm is disarmed before inspecting it since it has it's own battery inside.
Good luck

TMAllison · #15 09-16-2008, 05:04 PM

CCU is guideline and not considered as accurate as a multimeter directly on the batt.