2003 ML 270CDI - Alternator/Battery

[Sudesh]

Along with some other service work I'm doing on my ML, something else that had to be looked at was the alternator. About a week ago it gave up and the ML just suddenly died out while it was sitting idling.....Anyway I managed to get it home and test it the following day and all signs pointed to the Alternator. I removed it and sent it to be refurbished.

I received it back and got it installed, the ML fired up no problem and all seemed fine. Took it for a quick run and didnt notice anything unusual.........until.........I got it home and was sitting idling; the BAS/EPS light came on and from reading the hand book a low battery/voltage change can flick this light on. I done the reset by turning the steering full lock left to right but it didnt clear the light.

So I put it on the battery tester, the meter was only showing 13.4/13.5 at the most. I know it should be around 14.1/14.4 or so.

So could this be a case of the alternator wasnt refurbished right or any other ideas? The battery is about 6 months old but wondering could some damage have been done to the battery when the alternator went out? Tonite I have it on a charge and going to test again tomorrow to see what it shows.

 

[dokalj]

Sudesh, it is best to get the car on STAR.

When my BAS/ ESP light came on it was the wheel sensor.

I think you need to STAR it, unless you have another battery?

Remember if there is a fault, if you correct it the fault needs to be cleared.

Regards

dokalj

 

[tagnut]

Your alternator should output around 14.4V when running but even a new battery will very quickly drop to 13.2V once charging stops. It will then slowly drop to around 12.6V which is a normal fully charged state.

Fully discharging a lead acid battery can cause some damage (sulfation) but for a relatively new battery if this has just happened the once it will probably be ok

HTH

 

[Sudesh]

Took the alternator of again and had it bench tested, on the bench its output was over 14v, once installed on the ML gain, it's around 13.6/13.9 with no load i.e lights on or blower. BAS/EPS light is still on.

So I had the ML on Star today and while I was there asked the Merc Tech if the battery readout at 13.6/13.9 is right, he said thats about right for an ML!!! Anyone any thought on that?

Anyway done a read on the BAS/EPS and 2 faults came up
1. ROTARY STORED ACCELERATION SPEED SENSOR
2. Steering ANGLE SENSOR

He said its most likely the first one.

To be honest, I'm not having any driving issues of the ML at all! It drives fine, acceleration, brakes, traction are all good and starts no problem every day. So I'm going to change the speed sensor he mentioned tomorrow hopefully and see of the light goes out.