Have Mercedes Questions? Ask a Mechanic for Answers ASAP
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The first thing to check here is to have the battery tested to see if it has an intermittent fault like a bad cell that is acting up intermittently causing this issue here.I have seen this occur before and had to replace the battery.Inspect and make sure the battery cables are all o.k. as well with the cables not being loose or corroded in any way.
If these are o.k. I have seen issues with the Rear SAM control module/ecu that may cause this issue as well as the electronic ignition switch (EIS) that can fail or act up intermittently causing this as well.The fault codes will need checked using a scan tool or dealers SDS machine compatible with this model to see what codes are set and then from there the codes can be diagnosed to locate and repair the fault here.
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Usually if you have two keys/key fobs acting up the same way this isnt the key or key fob at fault here.If it was usually it would only be one key/key fob acting up and not both.
This fault here sounds to be an issue with the Rear SAM or the EIS (electronic ignition switch) itself as I have seen these fail and cause this fault here needing replaced for this issue.This will have to be tested further to be sure then the affected component replaced to correct this here.
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