Limp mode, causes, symptoms &cures, fixes.

1993-Present: C200 CDI, C220 CDI, C270 CDI, C180, C200 Kompressor, C230 Kompressor, C220, C230, C280, C300 C350, CGI & CDI BlueEfficiency variants
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newMercowner69
Pagoda
Posts: 121
Joined: Tue 24 Feb, 2015 5:00 pm
Model you own: w202
Location: Melbourne, Australia

Limp mode, causes, symptoms &cures, fixes.

Post by newMercowner69 » Sun 23 Dec, 2018 8:17 pm

What is "limp mode"?
It's causes, symptoms,
Cures&fixes?,
Compliments of the festive season/seasons greetings &merry Christmas 🎁🍷🎉🎄🎅🍰🎄🎁 to all OZ BENZ admins&members.

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Ivanerrol
Mercedes Demigod
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Joined: Sat 12 May, 2007 2:21 pm
Model you own: w204
Location: Melbourne

Re: Limp mode, causes, symptoms &cures, fixes.

Post by Ivanerrol » Sun 23 Dec, 2018 10:57 pm

Limp home mode :

Protection system on 722.6 forward transmissions.

Generally The ECU on the transmission has been given a number of fault codes. The ECU then prevents the transmission from changing out of second gear. Usually the car will not get above 30 - 40 km's per hour.

There is soft limp home and hard limp home.

Soft limp home is where the vehicle suddenly goes into a state where you cant go above 30 - 40 kph. Stop the car. Turn eng9ine off. remove key, reinsert and then start again - vehicle moves off as normal until the next limp home event occurs.

Hard limp home is where the vehicle is permanently locked in go slow.

Limp home engine issues are sometimes caused by a compilation of engine faults of many types.

Transmission issues usually cause hard limp home. - generally conductor plate. The mechanical of the 722.6 have been reputed to be very robust - as long as the transmission fluid is regularly changed. More of an issue is fluid getting onto the conductor plate and causing mayhem.

Simple engine issues such as O2 problems, MAF problems, ignition problems cause codes to be added up until so many will eventually get a message to the transmission ECU to go into limp home mode.

This issue n4eeds to be diagnosed by a Merc4edes Specialist with a correct MB scanner - STAR.

I had a mate with a '97 C200 with 722.6 which continually went into limp home mode. He had a mate who was a "European Car Specialist". In realty a Fiat mechanic. This Fiat mechanic had a generic scanner. Mate wasted hundreds of dollars on false diagnosis from this "European car Specialist"
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newMercowner69
Pagoda
Posts: 121
Joined: Tue 24 Feb, 2015 5:00 pm
Model you own: w202
Location: Melbourne, Australia

Re: Limp mode, causes, symptoms &cures, fixes.

Post by newMercowner69 » Mon 24 Dec, 2018 8:22 pm

Conductor (data?) plate &pin has been changed once in 3yrs,
Transmission fluid has also been changed in that time.

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