Pete S
Member
I thought I'd share this experience, in case there are other people out there with an older Marco Polo (i.e. pre 2014, the W639) We bought ours a year ago and have only used it this summer. Last time I went to prepare it for a trip, the engine warning light (the expensive one - "contact Mercedes immediately") stayed on. To cut a long story short, the local Norwegian Automobile Association workshop agreed to run the On Board Diagnostics (OBD) for me, and there were lots of faults showing. And then he said the first thing I want to share:
"The electronics on these old Vianos is a bit ropy if the battery runs a bit low or if they get hot, so I'll clear all the faults and we'll see if any of them come back"
And that was it. No faults, and no problems since. The second thing to share is that you can actually run the diagnostics yourself - and clear the faults yourself! There are several products on sale for the purpose, but the one I bought seems OK. A plug the size of a matchbox attaches to a connector visible underneath the dashboard on the left side (maybe "driver's side") of the vehicle, and it talks via Bluetooth to an app on a mobile phone. Bingo. Now I'm prepared for the next weird fault. This is the device I chose:
https://mobilscan.info/en/products/
If this is not available in UK there are several alternatives on the market, both more expensive and cheaper. Hope this might help somebody!
"The electronics on these old Vianos is a bit ropy if the battery runs a bit low or if they get hot, so I'll clear all the faults and we'll see if any of them come back"
And that was it. No faults, and no problems since. The second thing to share is that you can actually run the diagnostics yourself - and clear the faults yourself! There are several products on sale for the purpose, but the one I bought seems OK. A plug the size of a matchbox attaches to a connector visible underneath the dashboard on the left side (maybe "driver's side") of the vehicle, and it talks via Bluetooth to an app on a mobile phone. Bingo. Now I'm prepared for the next weird fault. This is the device I chose:
https://mobilscan.info/en/products/
If this is not available in UK there are several alternatives on the market, both more expensive and cheaper. Hope this might help somebody!
