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Dead Battery Cold Start see below any advice please!!! Thank You!!

M

MB Legacy

Messages
42
Hello people need your help with something, this morning when i tried starting my car everything was ok until i’ve put the key into the ignition and on the second click where the dashboard lights normally come on it did and then completely went off as if i had a dead Battery obviously it failed to start but nothing was working, kept pressing key fob to lock or unlock my car nothing was working so when decided to give up and head off to my other car to jump start all of a sudden everything came back on again it struggled to start but it did left it running for a good 20mins then decided to give it a 15 min drive but noticed than when i was coming to a stop Revs Drop as the car is about to die it goes after a while so im guess my Alternator and Battery looking to replace both asap so any help just wanted to make sure it was that as is the only thing i can think off. Thanks


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Hi,when engine running put meter on battery and you should get 14v which would prove alternator is working,
Battery would read 12v when engine not running.
Thanks steve
 
ECU need to relearn, this is why the idle drops to almost cutting out. There is a process to follow when battery has been removed/gone flat to help the ECU to get up and running again.
 
@SteveTypeRGT - Thank you tried it already and ordered a new Alternator along with a new Battery since it needed replacing.

@Blueboy - thank you for the reply how do i do the process when changing to a new battery??

Again guys thanks for the replies


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MB Legacy said:
@SteveTypeRGT - Thank you tried it already and ordered a new Alternator along with a new Battery since it needed replacing.

@Blueboy - thank you for the reply how do i do the process when changing to a new battery??

Again guys thanks for the replies ����


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Click to expand...

Undo Negative terminal first then Possitive

To put new battery back on connect Positive Terminal first the Negative Terminal
 
1. drive car til its warmed up.
2. turn car off, disconnect battery or pull ECU fuse out for around 30 secs.
3. put fuse back, start car, close hood
4. make sure everything is turned of (airco, radio, lights... don't press any pedals)
5. just let the car idle for 10 mins by itself
6. turn car off, then back on, and go for a drive like you normally do. it will take usually 100-400km to relearn the fuel trims.
 
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