Ml280 w164 M55 fault

[Gh1234]

I have a 07 ML280 that goes into limp mode. Reader came back with M55 fault. i have seen that this us a common problem but despite replacing the valve, which failed to clear the fault and placing a resistor as suggested in a few feeds I have read, It still goes into limp mode.
any other suggestions to fix this problem? Possible break in the wire has been suggested.
Thanks

 

[Uncle Benz]

Have you checked the failed motor hasn’t blown a fuse in the underbonnet fuse box?

 

[Gh1234]

I haven’t. Not sure if the technician has as its never been mentioned. Do you know which fuse it would be?
Thanks

 

[Wighty]

I haven’t. Not sure if the technician has as its never been mentioned. Do you know which fuse it would be?
Thanks

On the om642 E class it’s F44 15amp in the engine bay fuse box . I’ve got a vague memory that it’s not the same on the ML , I think member @bembo449 told me that , hopefully he can remember

 

[bembo449]

And he tends to agree that f44 is the one thats blows when that motor fails so unless you check the fuse aswell nothing will cure that particular fault

 

[Gh1234]

Morning
The fuse is fine. Still remains with no boost limp mode. Not sure what to do next. Maybe an Auto Electrician?
G

 

[Uncle Benz]

Did you have the motor unplugged with the resistor mod?

 

[Gh1234]

As far as im aware yes. Will check later but think it was disconnected.
The fault started off as a intermittent problem but became progressively worse to the point that it is in permanent limp mode. Although the EMS light doesnt always come on. Hoping the auto elec cab solve it but open to any ideas to sort it

 

[Wighty]

As far as im aware yes. Will check later but think it was disconnected.
The fault started off as a intermittent problem but became progressively worse to the point that it is in permanent limp mode. Although the EMS light doesnt always come on. Hoping the auto elec cab solve it but open to any ideas to sort it

Just to check that with the resistor mod , it’s a 4.7k ohm resistor into the middle two terminal of the motor

 

[bembo449]

What scan tool are you clearing the codes with ? Try disconnecting the battery for half an hour

 

[Gh1234]

Yeh, 4.7 across the terminals. Not sure what Lee is uses but mines a Launch123x.
will try the disconnect battery.
Only fault on the car and ive had 6years so really want it sorted. Thanks for your help so far!! g

 

[Wighty]

Yeh, 4.7 across the terminals. Not sure what Lee is uses but mines a Launch123x.
will try the disconnect battery.
Only fault on the car and ive had 6years so really want it sorted. Thanks for your help so far!! g

Sometimes the resistor doesn’t work if the arms from the motor to the swirl flaps are jammed or broken

 

[Gh1234]

The swirl valve was replaced with a new one. Just had a start nd it runs ok for about 1min the goes into limp mode. O delete the codes and the same thing happens.

 

[Gh1234]

Hi guys. Still having major problems with the m55 fault code. Done all the the things mentioned in previous messages and still getting the dame fault. Im told ot might be fixed by removing manifold and checking the arms (or something like that). Any more ideas would be a more than welcome.
g

 

[mersum1es]

As wighty said, if flaps are moving without control or jamming open, in may trigger fault. If M55 was changed, why flap function was not tested?

Check also EGR and all leak possibilities.

Unfortunately disconnecting battery probably gives more problems than solves them, it is different over 20 years old cars.

 

[Uncle Benz]

Do you have it permanently unplugged with the resistor across pins 2 and 3?

Have you checked the fuse box in the engine bay, driver's side for blown fuses, although the fuse for the m55 will usually give faults for the egr valve and turbo positioner too, as they share the same supply