My son has a 2012 Mazda 3 that 4 times in the last 18 months has stopped inexplicably on the freeway. One minute he is driving, the next the engine shuts off, no power steering, no radio, etc. He has been able to coast to the side of the freeway, turn off the ignition and restart. We have had various mechanics work on it. Even had a tech from Mazda dealership drive it back and forth to his house for 10 days (a 50 mile commute each way). No codes, nothing. No one can figure it out and it is becoming increasingly dangerous. The last time this happened was over a year ago, and again today. We live in San Diego, and if it makes any difference, all four times this happened to and from drives to L.A. 3 of 4 times within an 8 mile radius of LAX, two times near the same off ramp. This has happened day, night, no commonality there. Does ANYONE have any ideas? This is getting very dangerous.

 

Welcome to the forum

So the faulty diagnosis clue is that no one picked up on the no DTC or looked into the ECU records and counters?

Your ECU should the engine just quit as you described would have at least generated a pending DTC or a permeant DTC in the ECU until the condition causing the engine shut off to clear. The only reason not to have seen any would be a faulty ECU. The ECU should have at least been flashed with the most currently available update. IMHO.

 

Thank you Callisto! I will call the dealer to find out if they updated the SW when they had it for the 10 days originally.

 

SW? ok whats that???

 

Software.