To some observers it’s a perfect match — a big RV with a muscular engine capable of going the distance together with a versatile, petite and perky, zero-emission runabout with big batteries.
A vacation together beckons but it requires a quick hook up first. Everything lubricated? Check. Properly inflated? Check. The two are hot to trot but as soon as they begin driving away the wheels suddenly grind to a halt. What happened?!
According to GM service bulletin, #17-NA-257: Electronic Park Brake (EPB) Automatically Applies While Dolly Towing, “this condition may be caused when the grade of the car is estimated by the control module to be greater than 9%.”
In other words, when the frontal area becomes elevated to a great enough extent it triggers an automatic and sudden increase in friction. The Bolt EV is turned off when this happens.
The recommended fix is to remove the negative cable connection from the 12V battery until after fully arriving at the destination.
A tell-all video on YouTube documents the surprising and disturbing behavior.
Categories: General
Electric Revs 
This is very interesting. I picked up my 2017 Bolt and dolly towed it home about70 miles and had no problem. Planning on towing it behind my motorhome in a couple weeks and am now a bit nervous about it.
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As long as you follow the suggestion to disconnect the 12V battery (with the electric parking brake not engaged) after turning off the car you should be fine.
In the long run, they really need to change this behavior or introduce a specific “towing mode” that can be enabled through the infotainment screen. Having to disconnect the 12V battery should just be a short-term workaround. Let’s hope….
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I have yet to see any actual benefits from the Electronic Parking Brakes that are becoming commonplace in cars but I see plenty of shortcomings.
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