GLA220D 4matic W156 exhaust flap fault and replaced rear exhaust section

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mineauto

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Feb 7, 2021
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Location
Cirencester
Car
GLC 250D 4matic
Help needed.

My GLA220 went into limp mode recently a few times randomly. Each time the acceleration was affected and only eco mode selectable on the auto transmission.

I scanned for codes and found errors relating to the exhaust flap and exhaust flap actuator.

So I replaced the section of exhaust complete with the flap actuator, ordered direct from Benz spares, cleared the codes and expected this to fix it. It didn’t !

So now I’m wondering where to go next with diagnostic.

I know this unit talks to a drivetrain controller unit ( A 000 900 36 6 or N127, numbers from memory from looking at a manual earlier today, so I might be digit out ) so that is one possible item to check but I have no fault showing for that.

Has anyone else encountered this issue, ie replacing exhaust flap exhaust section, only to still have the fault?

Tomorrow I’m gonna examine closely the wiring loom and see if there is a short. This is protected by foil heat shield wrap but could be in the line of fire for getting a bit hot and shorting. Annoyingly, the actuator I removed works if I connect 5v across the terminals, however maybe the feedback controller from the old assembly is toast, don’t know how to test that.

Has anyone found the wiring loom to be fried?

Please comment even if you have similar problem with types other than GLA as Merc seem to use similar components on other vehicles.

Cheers,Jim
 

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Have you checked all your fuses? It could be the faulty unit popped a fuse, and the new one is not getting a supply.
 
Have you checked all your fuses? It could be the faulty unit popped a fuse, and the new one is not getting a supply.
Yes, tried that first after getting the same fault after swapping the unit.

Unless my fuse testing method can give a false positive. To test the fuses I checked the metal contacts on the top left and right for continuity.

Tested a fuse box in the engine bay and one in the footwell.

Is there another batch of fuses anywhere that I’m missing?
Cheers, Jim
 
UPDATE: for anyone who is interested I decided the best way to “teach” my flap was to give in and take it to Mercedes!

They quoted £174 per hour inc vat for diagnostic but I felt I had no choice.

They had a look and were equally perplexed. In the end the decided the new part I fitted was supplied faulty. So we waited a few days for one from Germany and they fitted it.

Hey presto, it worked! I had just been exceptionally unlucky and received a faulty new part.

The bill for all this? £ ZERO. As I had purchased the part from Mercedes it carried a 2 year parts and labour warranty, regardless of who fits it. They didn’t even charge me any diagnostic time.

So it “just” cost me £360 ish inc vat, the original cost of the parts. Well, plus the hassle and bemusement of why the repair I had made hadn’t worked.

Fair play to Mercedes, they were brilliant about it.
 
Good result 👍

This is one of the reasons that for the OM642 cooler seals I had done today they were replaced with the seals and a new oil cooler from Mercedes. It is leaks again soonish, Merc will apparently replaced and fit FoC
 
UPDATE: for anyone who is interested I decided the best way to “teach” my flap was to give in and take it to Mercedes!

They quoted £174 per hour inc vat for diagnostic but I felt I had no choice.

They had a look and were equally perplexed. In the end the decided the new part I fitted was supplied faulty. So we waited a few days for one from Germany and they fitted it.

Hey presto, it worked! I had just been exceptionally unlucky and received a faulty new part.

The bill for all this? £ ZERO. As I had purchased the part from Mercedes it carried a 2 year parts and labour warranty, regardless of who fits it. They didn’t even charge me any diagnostic time.

So it “just” cost me £360 ish inc vat, the original cost of the parts. Well, plus the hassle and bemusement of why the repair I had made hadn’t worked.

Fair play to Mercedes, they were brilliant about it.
Hello
Having exactly same issue with my gla. Do you or anyone know if flapmotor replacement will help or I will need to order full exhaust rear section with motor. Also where you have ordered and any part codes for the rearsection pipe and flapmotor? Cheers Matti
 
Hello
Having exactly same issue with my gla. Do you or anyone know if flapmotor replacement will help or I will need to order full exhaust rear section with motor. Also where you have ordered and any part codes for the rearsection pipe and flapmotor? Cheers Matti
Hi Matti,

You could try changing just the motor unit but you’ll only find that as a breaker part, Mercedes don’t sell them separately.

from Mercedes you buy a mid section pipe with the motor/actuator fitted ( and 2 clamps ). In the factory the pipe is one big long one from back of the engine to the rear but that isn’t how they sell the spares, otherwise you’d be buying a section with catalytic box and rear silencer box when you don’t need it. Plus it’s maybe a bit harder to swap something that big.

I’ll have a look now for the invoice for part numbers. You just ordered it from your local Mercedes dealer. Ask to be put through to spares dept.

Cheers, Jim
 
Hi Matti,

You could try changing just the motor unit but you’ll only find that as a breaker part, Mercedes don’t sell them separately.

from Mercedes you buy a mid section pipe with the motor/actuator fitted ( and 2 clamps ). In the factory the pipe is one big long one from back of the engine to the rear but that isn’t how they sell the spares, otherwise you’d be buying a section with catalytic box and rear silencer box when you don’t need it. Plus it’s maybe a bit harder to swap something that big.

I’ll have a look now for the invoice for part numbers. You just ordered it from your local Mercedes dealer. Ask to be put through to spares dept.

Cheers, Jim
 

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Hi Jim,

Thanks, appreciate a lot your reply. I will proceed with local mb dealer and check if part is available through spare department.

Will update later how it went.

Cheers Matti
 
🙄.. it’s just I am getting mine sorted on the 4th.. I believe it’s just the flap motor .. so hopefully Dave me ££
 
🙄.. it’s just I am getting mine sorted on the 4th.. I believe it’s just the flap motor .. so hopefully Dave me ££
Did this solve it?

I've got a similar problem on my gla 220d 2016 - fault codes for exhaust flap actuator and limp mode. I removed the actuator and the flap itself is free to move so not seized. I also have access to a working star/ xentry diagnostics so I can test via that to move the flap to different position, however when trying to test a week or so ago, xentry says the external temp needs to be 10C or above or it doesn't let the test run (assume due to the possibility of the flap being frozen or blocked by ice below this temp). The issue has only now reappeared during the warmer weather, so I am guessing the flap is also not used when the ambient is below 10C.

So thinking of getting a new actuator to try - they seem to be around £200. I see I can 'teach' the new one in star.
 
hi tobes

interesting i thought it was plug and play, i have mine disconnected was great for a few months until last Saturday after 80 miles, got home ok but after sitting for an hour in the drive and a quick spin all good again
how do mean : I can 'teach' the new one in star.
 
Hi John, It seems as though the unit needs to be 'taught' through Star - there is an option on the laptop to enable this procedure. I guess it does something like moving the motor to the extremes (i.e. fully open to fully closed) and measures the feedback so it can work out the angles of the flap between. It does say only to do this if a new unit has been fitted.

If i manually move the flap/motor I can see the angle change on Xentry/ Star, so there is some feedback there. I'm going to try testing again this weekend when hopefully the temp will be above 10C so it will allow me to move it via the laptop. It seems that you can select an angle to move it to so you can check it moved to that angle. I am guessing it won't move correctly and that is the problem. I'll post back here how it goes!
 
Well tried it and didn't move - so I've now got a new actuator on order..
 
Just to update this - received the new motor (p/n A0009061201), and fitted it. I tested the old unit with star before changing and this time it was moving - however compared to the new one it was slow. I did the 'teach' routine in star on the new unit and this worked OK as far as I can tell (not really sure how essential this step is).

All seems good now so far!
 

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