2003 R230 SL EASY-ENTRY STOPPED WORKING

[television]

Joining up the batteries in the wrong order, will put the lamp on, I did it myself before I knew better and got the red lamp but that was instant.

Later in the day I will look at the complete circuit of the battery module.

As it does the same thing all the time it does rather discount connection as if connections, the faults would be more random.

I would put a voltmeter directly over the battery and see if there is any change at all when the warning lamp comes on

 

[COVERT1982]

l have only checked the batteries with the Battery light on and both batteries are around 13.5 volts. The MB service already checked the batteries and stated that the charge rate is good?

 

[television]

13.5 is a little on the low side, not a lot, something must change at the point when the lamp comes on. 13.5 only leaves 1 volt to charge and that is not that much for an AGM battery, but I will check mine this afternoon and see what that runs at.

 

[Alex Crow]

Not sure if you have read all this yet COVERT1982, but you must... http://www.mercedestechstore.com/pdfs/R230_technician/318 HO R230 Dual Battery System 11-28-02.pdf

 

[television]

Now I wonder if the voltage reg is out of spec, mine runs at the correct voltage of 13.85v

 

[television]

Not sure if you have read all this yet COVERT1982, but you must... http://www.mercedestechstore.com/pdfs/R230_technician/318 HO R230 Dual Battery System 11-28-02.pdf

I put that link up Alex much earlier on in the thread

 

[COVERT1982]

I have checked the battery report from the 2/1/2015 (first time on star) and the start battery was 13.0 volts and the rear battery 12.56 volts.
The report states "batteries and charge rate in good order"
It's the Red battery fault light which is on.
l have just rechecked the batteries, front is 14.3 and the rear 13.95
And sorry Alex l have not read the hand out, l have been trying the suggestions that Malcolm has given me but l will today.

 

[television]

So the alternator is fine , and voltages correct, this just leaves the battery module as I see it. re the 2 relays one connects both batteries together if the needs be and the other operates the consumers off, and neither of these have anything to do with the charge lamp. If the voltage stays at 13.8 volt or more even with the lamp on there is not that much more to it.

If these control units can be damaged or not if left after batteries connected in the wrong order I do not know. As they are on the CAN maybe going into the CAN to see if anything there.

 

[COVERT1982]

l have checked the two Star reports that l have and it does not list anything about a CAN test, so l take it the vehicle will have to be rechecked by MB service centre on Star?
And will I have to request a CAN test?
The funny thing is that both reports 40 days apart list the same faults even though l have replaced the relay.

 

[television]

I just do not know what else to say or do, unless Alex has any idea's

 

[television]

What I would do is to go the the control unit and see what what comes up, and if not conclusive I would have a look on the CAN to see if anything on there, but that would be my way.

I have found another paper that I will send to you.

 

[COVERT1982]

thanks for your Malcolm, we will see if Alex has something to add

 

[Alex Crow]

...The funny thing is that both reports 40 days apart list the same faults even though l have replaced the relay.

The one I mentioned earlier, giving the same/similar fault scenario was also pointing to one of the relays (probably K57, cannot remember for sure). We did replace it, but the same fault code did keep coming back.

 

[television]

Thinking still on this the K57 just brings the starter battery into the circuit to be charged, it is just a single pole relay. The K75 will have current passing through the contacts all the time. These are both heavy duty relays.

So far in my life I have been able to remove the cover from any relay to be able to inspect the condition of the points by using a magnifying glass in some cases and clean the contacts if the need be.

We know that when the car is first started that max current in these circuits is flowing, we also know that heavy currents can arc themselves to give a good contact, at the same time we know that this does not happen with low currents.

So after much thought, and the Star read out I would remove the cases and inspect the condition of the points. They can be cleaned up to remove the carbon content using silicon carbide paper about 220 grade for this size of contact. The case/cover can be glued back on if the lugs/clips break, it could take these out of the picture to save replacing at this point in time.

Worst of all we know that this is a rare problem on a 230.

 

[COVERT1982]

Alex, do you think that it’s something that l will just have to get used to?
l have already replaced relay K57.
It sounds like l will not be able to fix it.
The funny thing today is that l used the car, the first time the light came on as soon as the car started and second time it did not (moved the car down the drive way)
Thanks Alex and Malcolm for your help on this.

 

[COVERT1982]

Can l just swap the old/or K57 relay with the K75, it has the same part number?

 

[television]

Can l just swap the old/or K57 relay with the K75, it has the same part number?

Same part number then yes.

 

[COVERT1982]

OK will give it a go

 

[Alex Crow]

I believe the two relays are actually different.

 

[COVERT1982]

l was told that its the same relay, l will have to check with the MB spare parts department