2009 CLS Grand Edition Limp mode when warm

[dan90210]

So as per title

From a cold start up the car runs absolutely fine and will continue to run fine for endless miles until the ignition is switch off.

When the car is restarted it'll only drive I'm what feels like limp mode, max revs 1500 rpm and no or little accelerator.

When the car is turned off and allowed to cool it's fine again.

Any ideas on where to start looking?

I've had a previous fault code showing the O2 sensor which I drove on for a while but that's been changed now for a new one and the code for that hasn't returned.

So from cold it'll drive faultless for at least 200 miles as I've done that. As soon as I shut it off and restart max 1500 rpm until it cools down again!

Scratching my head with this one!

 

[sonic]

First off you need to get the codes read.

 

[Wighty]

So as per title

From a cold start up the car runs absolutely fine and will continue to run fine for endless miles until the ignition is switch off.

When the car is restarted it'll only drive I'm what feels like limp mode, max revs 1500 rpm and no or little accelerator.

When the car is turned off and allowed to cool it's fine again.

Any ideas on where to start looking?

I've had a previous fault code showing the O2 sensor which I drove on for a while but that's been changed now for a new one and the code for that hasn't returned.

So from cold it'll drive faultless for at least 200 miles as I've done that. As soon as I shut it off and restart max 1500 rpm until it cools down again!

Scratching my head with this one!

The O2 sensor doesn’t cause limp mode .
If you are handy , you can remove and clean the actuator with electrical spray cleaner and put some high temp grease on the worm gear . Check that the metal wires that leave the outside of the pcb board haven’t broken .
Remove the exhaust back pressure sensor and spray clean the hole on the underside to get the black gunk out .
Try a 4.7k ohm resistor (£1) plugged into the middle 2 contacts on the electrical supply to the swirl flap motor which is under the black bat wing .
Remove and spray clean the egr .
These all share the same fuse in the engine bay box on the om642 . 15amp on my w211 …might be F44 on mine ?
These are all free jobs that may well address some of the limp mode om642 issues .

 

[dan90210]

First off you need to get the codes read.

Hi.

No stored codes.

Previous O2 sensor code but that's been replaced and no further codes

 

[dan90210]

The O2 sensor doesn’t cause limp mode .
If you are handy , you can remove and clean the actuator with electrical spray cleaner and put some high temp grease on the worm gear . Check that the metal wires that leave the outside of the pcb board haven’t broken .
Remove the exhaust back pressure sensor and spray clean the hole on the underside to get the black gunk out .
Try a 4.7k ohm resistor (£1) plugged into the middle 2 contacts on the electrical supply to the swirl flap motor which is under the black bat wing .
Remove and spray clean the egr .
These all share the same fuse in the engine bay box on the om642 . 15amp on my w211 …might be F44 on mine ?
These are all free jobs that may well address some of the limp mode om642 issues .

Which actuator are you describing?

 

[Wighty]

Which actuator are you describing?

The black box on the side of the turbo .

OM642 Actuator clean out and refit .

Due to the sunshine , I had done this job 3-4 years ago so I thought I would remove the actuator again and clean it out . Turbo shield removed , 3 bolts . Then the split ring on the actuator arm popped off very carefully you could tie some cotton on it , but I only did this when I refitted it ...

forums.mercedesclub.org.uk

 

[Wighty]

Which actuator are you describing?

Is this the diesel ? If it’s not ignore every have ever said .

 

[dan90210]

Is this the diesel ? If it’s not ignore every have ever said .

Yes 3.0 diesel.

I'll give those a go.

I did wonder about the turbo actuator myself.

Just seems weird that everything is fine until a hot restart. I'm thinking something isn't returning to its expected position at ignition off

 

[Wighty]

Yes 3.0 diesel.

I'll give those a go.

I did wonder about the turbo actuator myself.

Just seems weird that everything is fine until a hot restart. I'm thinking something isn't returning to its expect position at ignition off

Someone might be able to advise if the crankshaft position sensor on the side of the engine might behave a bit like this ??

 

[dan90210]

I've noticed that "Calculated LOAD value" on my scan tool is 0.0% when cold and anything up to 30% when the engine is warm with ignition on and engine off.

Is that a clue?

 

[Wighty]

I've noticed that "Calculated LOAD value" on my scan tool is 0.0% when cold and anything up to 30% when the engine is warm with ignition on and engine off.

Is that a clue?

That’s way above my pay grade buddy

 

[onefortheroad]

If it's going limp ,codes must be there , Shirley??

Afaik a poor crank sensor causes , hard starts not limp mode.

 

[dan90210]

I've now checked the actuator at the turbo and marked the position where

That’s way above my pay grade buddy

 

[dan90210]

If it's going limp ,codes must be there , Shirley??

Afaik a poor crank sensor causes , hard starts not limp mode.

Nope no Dash light lit and no stored codes at all.... Well "yet" anyway. Been going on for a couple of weeks now so I'd have expected a code by now.

I was hoping the new O2 sensor would have fixed since that was the only code showing on the scan tool.

That's been replaced, codes erased, and no further codes present

 

[onefortheroad]

Nope no Dash light lit and no stored codes at all.... Well "yet" anyway. Been going on for a couple of weeks now so I'd have expected a code by now.

I was hoping the new O2 sensor would have fixed since that was the only code showing on the scan tool.

That's been replaced, codes erased, and no further codes present

Eml comes on after 6 or 7 consecutive same faults .

O2 sensor as mentioned won't cause limp mode.

don't rule out the transmission if it's an automatic.

If you've 2 keys , try the other . Long shot but can cause issues .

 

[dan90210]

So it's in limp mode again so been out to check the position of the variable vane arm on the turbo, that matches the position for when it's working.

Same with the throttle plate after the MAF sensor, it's in the same position as before ie at 90° to the intake.

That's not to say they aren't faulty but they "look" OK and have returned to their ignition on engine off position nicely.

Still no codes.

You mentioned gearbox. Yes it's an auto box. What can I check there?

 

[dan90210]

And in a few hours it'll all be back to normal again!

 

[KennyN]

What code reader are you using ?

Maybe worth paying for a scan at a MB Indy`s who will have access to the factory level of diagnostics.

K

 

[onefortheroad]

And in a few hours it'll all be back to normal again!

So your saying from a cold start , fuel permitting,you could drive for hours, upto 90 degrees , until it would run out of fuel. ??

Turn it off when hot and you go limp ?

 

[onefortheroad]

That’s way above my pay grade buddy

Leave it to me buddy , I'm on a fortune