CLC 200K - SAFETY MODE AGAIN - Could it be dust affecting it? Or a sensor affected by Dust...

[evan86clc200]

Hi All,

After 'fixing my car' which had been in safety mode, only drove in 2nd and jolted when it went into drive or reverse with a new battery, cleaning the MAF and clearing the codes , the problem came back yesterday, after 2 weeks of smooth sailing.
Here's the question, it happened after I had driven for around 3 miles on a very dusty gravel road, and a week ago the same happened after driving on a similar road, but luckily then i turned the engine off then on and the problem disappeared.
It still says fault code P205A - which is redundant tank sensor - it is a petrol kompressor, not diesel.

My question is - is there are sensor that could be affected by gravel and dirt roads? As this has been the main constant over the last month or so with this issue....

Secondly, is there any way to fully reset the ECU and TCM or transmission control unit via the battery or some trick without an MB Diagnostics machine? The last time, i took it to a friends garage, they plugged it in to their Pro Diagnostics machine, cleared all codes and off she went, changing perfectly without issue.

LAstly, my tyres had been incorrectly inflated, too much air so i let some out last night in the hope that could be part f the issue.

the ATF fluid is fine, gearbox runs smoothly, I have check the fuses, just can't work out what it could be, maybe the P205A code?

Any help would be appreciated. I am planning on driving it back on the 8th August from Norway, which is 2000 km and that would be a pain at 50kmh!

 

[markjay]

1. Did the garage provide you with a printout of the fault codes before erasing them?

2. Did the garage use MB STAR diagnostic computer? The reason for asking is that generic code scanners can only access a small proportion of the car's ECUs and may miss some relevant fault codes.

3. Keep in mind that erasing the old fault codes simply clears the internal system log, but it does not fix anything as such. The reason for doing it is so that the car can be driven then rescanned to see which of the stored fault codes related to historical events and which persist and keep coming back.

4. Did the EML come-up at any time? Keep in mind that yours is the 1.8L Supercharged M271 engine which is prone to suffering from blocked engine breather, split vacuum hose under the air filter box, and from premature timing gear failure (typically at around the 100,000 miles mark).

5. I am assuming the 5g box had its ATF and filter changed as per schedule, and the ATF level checked? The common issues with these boxes are leaking pilot bush, and electroplate failure.

6. As for driving on gravel... I don't know if dust ingress can cause the issues you describe, but keep in mind that driving on gravel will cause vibration which in turn can affect any lose wires or electrical connectors.

 

[evan86clc200]

Hi Mark,

Thanks for your message.
1. Yes they did, they scanned the entire car.
2. Yes.
3. they scanned it after and the only faults were Telecomms and overhead control panel
4. EML? I cannot see that on the printout, what is EML? I have not checked a vacuum hose under the air filter box, I have the air filter out now, where exactly should I check?
5. It was fully serviced around 18 months ago, with new ATF fluid and also filter change etc, the transmission works absolutely perfectly, when this fault is not putting it in limp mode. ATF level checked and is spot on.
6 Good point, I think it must be something electrical.

I have now checked the printout, the only 'Current and Stored' fault was EGS53 (CAN): Electronic transmission control
2767 (P2767) No signal from component 'Y3/6n3 (RPM Sensor 3)
That must be the issue (wish I had checked before) what does that mean and can I check it myself?

Thanks so much again

 

[evan86clc200]

This fault did clear though after the diagnostics???...

 

[PobodY]

It might be as simple as driving on gravel roads is giving a connector somewhere a bit of a shake; it breaks a connection and the ECU registers the fault. - Given that you're getting something associated with the transmission control, maybe that's where the (slightly) loose connection is?

I'm basing this on the same logic as the SRS fault I sometimes see; there's not really anything wrong other than a connector under the seat comes loose... especially when the car has been bumping over a rough road.

 

[evan86clc200]

Thanks for that!

Where is the connector under the seat? Is it under the drivers side seat? It always realted to bumps and gravel, when it first started potholes caused the issue, now its more gravel roads as there are less potholes here but more bad gravel roads

cheers

 

[markjay]

EML = Engine Management Light

That's the amber/yellow light in the instrument cluster that comes on when there's an engine-related fault.

 

[Codger49]

I had dtc P2767 on my 2006 CLK280 with 7 speed transmission (722.9).

It required a new electroplate for the gearbox valve chest to fix.

Replacement plates require SCN coding online to MB's servers, but getting your own plate repaired, thus preserving its identity, avoids this.

 

[evan86clc200]

Thanks alot. No the EML never came on, it isn't on now either, just jolts when I put it in drive and is in safety mode.

If it was the plate, how woukd it have been fine for the last 2 week's? I'm just curious if I can clear the codes again and drive it back to England. I will likely sell it then, nd buy one when i come back to Norway as I am planning on staying here and this car is giving me headaches.

I have been thinking about buying a icarsoft MBII scanner, using that to help get home and when I come back here get an ML (02 or 03, 04) and then I have the scanner.

Could any damage be caused if I clear the faults and drive it 2000km to get home?

Thanks

 

[PobodY]

Thanks for that!

Where is the connector under the seat? Is it under the drivers side seat? It always realted to bumps and gravel, when it first started potholes caused the issue, now its more gravel roads as there are less potholes here but more bad gravel roads

cheers

For the passenger occupancy, and seat belt sensor(s), it's under the passenger seat on a CLK. - This may not be in any way relevant to your problem; I'm just saying that after 10 or more years some of the connections may not be as solid as they once were.

Hopefully it's not the electroplate, but if it's throwing transmission errors it's a possibility.

 

[markjay]

...I'm just curious if I can clear the codes again and drive it back to England...

As previously said, clearing the codes is a diagnostic process and won't change the way the car drives.

...I have been thinking about buying a icarsoft MBII scanner...

If you are buying new, then the latest version is iCarsoft MB 2.0 (which superseded the old MB II). But either way it's a diagnostic tool and won't 'get you home' as such.

 

[Old spanners]

Posted this for you before.
The code is used for this on a petrol car.
As suggested at the end I'd check the fuel pump connections.
Found this it should explain your fault as it's connected to the speed sensor.
P205A Mercedes-Benz Auto Trouble Code With All Car Models | Auto Trouble Codes - AutoTroubleCode.com
P205A Mercedes-Benz Auto Trouble Code
P205A Mercedes-Benz OBD2 reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.

Remove the air filter box assembly so you can access the transmission range switch. Turn the key to the ON position, but do not start the vehicle. Move the shifter to the neutral position. Align the alignment holes between the switch and the shift lever. Insert a 5mm drill bit into the adjustment hole to verify the proper alignment for the neutral position.

P205A Mercedes-Benz Possible Solution:
Vehicle Speed Sensor (VSS) Out of Self Test Range Indicates the VSS input signal is out of Self Test range. If the PCM detects a VSS input signal any time during Self Test, a DTC P1501 will be set and the test will abort. Noisy VSS input signal from Radio Frequency Interference/ Electro-Magnetic Interference (RFI/EMI) external sources such as ignition wires, charging circuit or after market equipment. Check for VSS input to be 0 mph when vehicle transmission is in Park.
P205A Mercedes-Benz Trouble Repair :

With P205A Mercedes-Benz code so start with the basics like a fuel pressure and fuel volume test. Or, you can start on the electrical side by doing a voltage drop on both the power and ground connections for the fuel pump. Some shops are reporting corrosion on the fuel pump ground that reduces power and fuel pressure.

This should give you a more focused and better chance to find the problem.

 

[Codger49]

I understand the P2767 can be an intermittent failure for several years before it goes hard.

It normally manifests itself by refusing to change up from 2nd (or maybe 3rd) gear but switching the ignition off and on clears the fault The P2767 stays as a stored fault in the car's memory, but the gearbox changes OK).

When I bought the CLK280, it failed 4 days later, but an ignition off and on stopped it from re-appearing before I had the plate replaced about a month later. Checking the invoices that came with the car, I found a Star printout from a couple of years (about 8k miles) previously showing the P2767. No invoice to show it had been replaced before I did it.

My guess is that you would be able to get back to England.

 

[merc85]

Yep sounds like the conductor plate tome too.