C200K Estate 2006 Electrical fault

[RickC]

Hi

I have a continuous electrical issue with my car and wondered if anyone can help?

The Bat/Alt light started coming on infrequently initially with no running issues. Then various other problems crept in - ABS light, TCS light, Light sensor warning, Lights dimming, radio turning off, stuck in gear etc. Then it runs fine for a while before it all starts again. The car has had the following, none of which has resolved the situation.

3 alternators! It now has the correct Bosch one
New battery
Replacement front SAM unit

The Alt intermittently seems not to charge on tick over if there is a load (Aircon, lights etc).

I have a brilliant independent specialist who is not charging me for the work he is doing and he is coming to the conclusion that it is an ECU problem. The diagnostic says that the current is spiking with an alt feed problem, but we can't find it.

The ECU cost will hardly be worth the value of the car, but I love it...

Can anyone help?

Thanks

Rick

 

[RickC]

Hi

Can anyone help with my post above?

Thanks

 

[Oldspanners]

Hi

Can anyone help with my post above?

Thanks

Have you had all the earths to the engine checked for corrosion?

 

[RickC]

Have you had all the earths to the engine checked for corrosion?

 

[RickC]

Hi

Thanks so much for replying. Yes the earths are all good-in fact the specialist added an extra one to make sure

 

[Oldspanners]

Hi

Thanks so much for replying. Yes the earths are all good-in fact the specialist added an extra one to make sure

Obviously just guessing but apart from the ECU looks to be a wiring fault from the charging circuit.
Has the mechanic tried wiring the alternator temporarily to rule out a broken/cracked wire in the harness?
That could cause a spike and the intermittent no charge.

 

[RickC]

Thanks again

Obviously just guessing but apart from the ECU looks to be a wiring fault from the charging circuit.
Has the mechanic tried wiring the alternator temporarily to rule out a broken/cracked wire in the harness?
That could cause a spike and the intermittent no charge.

.

 

[RickC]

Thanks again.

No, not tried that and it is a good idea

 

[RickC]

Thanks again.

No, not tried that and it is a good idea

Further to this, the vehicle often doesnt charge at tickover. There is a signal from the exciter wire but nothing from the alt. Would this rule out the ECU and in spite of the fact it has had 3 alternators, still point to an alternator fault? I read somewhere that these cars are very sensitive to the exact model of alt?

 

[Oldspanners]

Further to this, the vehicle often doesnt charge at tickover. There is a signal from the exciter wire but nothing from the alt. Would this rule out the ECU and in spite of the fact it has had 3 alternators, still point to an alternator fault? I read somewhere that these cars are very sensitive to the exact model of alt?

You would need to check that there is charging voltage on the alternator itself directly to rule out any wiring problem when this occurs.

 

[Steve@Avantgarde]

Check the earth strap that is on the gearbox and also the wiring that controls terminal 61 from the alternator to the front SAM and engine ECU. Its the multiplug that goes in the back of the alternator.

 

[RickC]

Check the earth strap that is on the gearbox and also the wiring that controls terminal 61 from the alternator to the front SAM and engine ECU. Its the multiplug that goes in the back of the alternator.

Thanks for the help so far. No joy I am afraid. My specialist is stumped also.

Does anyone know of a Mercedes electrician in the Hampshire area or alternatively anyone who can renovate ECUs as I think this is the only thing left..

Thanks again

 

[Steve@Avantgarde]

So lets go back to the beginning and to the basics. What fault codes are being stored in every unit that relates to either under voltage or loss of communication?

From there you should be able to establish a link to where all those units are powered from, it might be a CAN data link, a solder joint, even loss of an earth somewhere.

 

[LostKiwi]

Have you checked the earthing points for the ECU and front SAM? Undo them and clean them up as opposed to simple visual checks.

 

[RickC]

Thanks for all the comments guys. Yes, earths all now undone and checked.

The fault codes are:

2061-001 Alt serial interface, Electrical fault
2061-002 Same Mechanical Fault
2062-001 Same Generator or regulator faulty
2062-002 Same No connection to control

 

[RickC]

Also noticed today that the red light went out when i put the car in Park?

 

[LostKiwi]

https://www.underhoodservice.com/tech-tip-mercedes-benz-battery-dash-light-illuminated/

 

[RickC]

Thanks Lost Kiwi

 

[RickC]

SOLVED!

Thanks everyone. It was a poor earth strap (corroded) and a faulty VR

 

[mattkh]

SOLVED!

Thanks everyone. It was a poor earth strap (corroded) and a faulty VR

Which earth strap was it?