We recently took our 2016 Ford 10 cyl. (Motorhome) to our mechanic for oil change and check up, prior to big trip. Everything looked great and vehicle ran great before and after this visit. We then took it in for emissions testing. When we first arrived, we were told they were having trouble with their “machine” and couldn’t help us. Then as we were leaving, they called us back and said all was good and ready to go. The truck passed emissions testing but we were not one block away and truck started to jerk and sputter, losing power. We had it towed to our mechanic who ran diagnostic check and said all showed fine, no problems evident. We again went to drive off and not a block away, the same thing happened. We limped back to the garage. So, we wonder if the emissions testing “machine” caused damage and what kind of damage? Our mechanic can’t see anything when he runs diagnostic, so now guessing a “celluloid starter”. Thoughts? Suggestions? Help?

  • Welcome to Motor Vehicle Maintenance & Repair! Mar 27, 2021 at 10:57
  • Hi Laura - the mechanic was probably referring to the "starter solenoid". That's the part that connects the electric starter motor to the engine and tries to get things going. I wouldn't think that that would affect the ability of the vehicle to run at a steady state, though.
    – Bob Cross
    Mar 29, 2021 at 13:10

1 Answer 1


It's possible that the testing OBD system could cause damage to the car's systems, but it's very unlikely. The reader could have sent a surge of power to the ECU, which is the engine's brain, but that would probably have shorted it out and it wouldn't even start up. That's not to say that the mechanic couldn't have damaged something and caused your problem, it's just not likely to be caused by the OBD equipment.

Your mechanic saying there's no problem evident is a hoot, you obviously wouldn't have had it towed if there wasn't a serious issue. There's no such thing as a celluloid starter, starter solenoid maybe? If that was the problem it wouldn't turn over in the first place. The possibilities are:

  1. Your mechanic broke something in the emissions test: if so they should fix it free
  2. Coincidence, something broke and it just happened to be when you left the emissions test: they won't fix it for free but they should figure it out so they know whether they caused it or not, and then they can quote for a fix

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .