We have to date seen plenty of damaged diagnostic tools arrive at our door step and we have found often a common problem during usage. The garage owner depends on the workshop technician to do vehicle diagnostics and provides them with the capable tool. However we have seen that simple prevention during operation will save you an unneeded trip to our workshop with what is left of your trusty diagnostic unit. It does not matter if you are using the latest Snap On, Launch, Autel, Carmen or Bosch unit all of these will suffer the same effect.

If the tested vehicle is a non runner the chances that the battery will be flat when it arrives due to customer abuse, is great. We as standard practice connect our trusty diagnostic unit to read for possible solutions.

We in our haste use a jumper battery or boost pack to get this vehicle to start which is not the problem, but once it starts is where the drama also starts. Remember the little “boost button” on your charger will also put you in an unhappy place. We assume you know this, so let’s continue.

So once it starts we are in a happy state due to the achievement of getting it to run, we whip off the boost pack or charger, and this is where all hell breaks loose as the alternator immediately spikes the voltage due to no resistance from the boost pack or charger. Our little diagnostic unit which is still attached cannot fend off this voltage increase and fries all the internal components. Check “Automotives Idiot Guide 101”

And to date the standard response is “It cannot be damaged, as it was just working a minute ago.” Too late, the damage has been done.. As they say in the classics, rather difficult to put the smoke back in the tool.

So the long and the short is, never do diagnostics while trying to jump start any vehicle. Rather remove the battery and recharge before any diagnostics take place. And “no I did nothing, it just stopped working”, will not lighten your bill.

Take care and happy diagnostics.