MB CLC200K 2008 P205A code Help Needed

[evan86clc200]

Hi all,

Thanks alot in advance of any responses.

My car is in a limp mode, it drives but does not change up. It showed 3 fault codes on my reader, I cleaned the MAF in the holder, noticed the bottom clip of the air intake manifold was undone, and cleared faults.

Only one appears now. The car was jolting into Drive and Reverse and since cleaning the MAF, this has stopped. BUT, it STILL won't change gears. The Transmission fluid is full, was working just fine, so I am confident(ish) it is something electrical. I drove down a long dirty dusty road with bumps just before the problem occurred, so it makes sense that the MAF got dirty.

The P205A code is a Reductant Tank Temperature Sensor Circuit - according to google, says it could be faulty.

Would disconnecting the negative help clear this code? When I clear it with my OBDII reader, it just comes back on straight away.

The battery was sitting at 12.1-12.2 volts and is 10 years old, I charged it and now its 12.5v.

Any advice on why it is not changing, where this sensor is located would be greatly appreciated.

I m on holiday with the car in Europes most expensive country, Norway, so i really need to work this out myself.

BR

 

[markmifsud]

A 10 year old batter that wont take a charge? I suspect the battery is on the way out and a low voltage can cause no end of problems. if it were me, I would get the battery checked first and replace if needed, then see what happens.

 

[evan86clc200]

Thanks Mark. Maybe I wasn't clear, the battery was at 12.1-12.2 v when the engine was off. After charging its at 12.5v now, thats about normal isn't it?
To shed some more light. The timing chain snapped, a little under a year ago. The car sat still for 7 months until I replaced the engine, so . the battery has sat connected for some time. that being said, straight after the new engine went in (second hand of course) i drove 2100 kilometres to Norway. A couple of times the power dropped, I turned the engine on and off as it wouldn't go past 3000rpm, I suspect the MAF had gotten dirty or collected dust etc, but then again, I guess it could just be that the battery is not right. Is 12.5v acceptable?

 

[evan86clc200]

Correction - it is at 12.4v now - so overnight when charging only increased by .2-.3volts. Would you say 12.4v is too low before starting the car? It fires right up. But could that be the isssue? A battery here will be a couple of hundred, but if it's really worth changing then I will.

I'm missing so much fishing when it's not drivable

 

[190]

12.4 V is not a fully charged battery. Assuming the battery is reasonably healthy it indicates 70% charge at best. It may well start the car but that's not the point. I would fully charge it to a minimum of 12.6 volts measured after an minimum of 3 hours rest then get it load tested.

 

[evan86clc200]

Thank you very much. I took this advice, went to a Battery shop, they tested it, said their reading was 12.5-6, so the internal reading given by the car at that time was 12.2-3. Strange how the car gave a different reading. It was holding around 600 amps when they tested it, and when knew the battery is 850 amps or so. They said its definately the original battery and will have some wear and not perform as well ad it should. When the car was running and they tested it again it rose to 14. something.
They lent me a proper charger, and when I plugged it in just now it indicated 50% battery charge. I guess the old battery is on it's way out. I will charge it fully overnight and take it back to be tested again.

Just to confirm, the fault code could be related to this?

as prior to it going into this emergency mode it was running just fine, no reported issues at all.

Thanks for all your help so far, feel like I am getting somewhere now.

 

[evan86clc200]

Aha, so I think the battery must be on it's way out.

I used the charger the shop lent me. 2 hours or just under and it went from 50% indicated to Fully charged. I guess that cant be right. Surely it would take way longer even with a decent charger?

 

[Ted]

Well, lets assume that it’s a 100amp hour battery.
That means that to go from 50% to 100% with a five amp charge would take ten hours.
Or a ten amp charge would take five hours.
Actually a little longer due to losses.
That’s assuming the charger is indicating correctly.

 

[evan86clc200]

Thats great, so it is almost certainly the battery is that a culprit. and Hopefully the main culprit!
I will go and buy a new one tomorrow, stick it in and see if the problem goes away. The car was sat for 7 months with the battery connected before i put a replacement engine in, so I guess its had a relatively hard life.
I'll let you guys know what the outcome is. Thanks again!

 

[evan86clc200]

Ah so annoying. changed the battery - propble still the same, jolts a little when you go into drive, doesnt change up, stays in one gear. No fault codes are showing. My diagnostic machine says some grey codes can only be cleared by the ECU and may take a few journeys to clear.

ANY advice?