My 2015 Elantra with 130K miles has developed a problem It stalls occasionally, and then the Tachometer goes to 0 and stays there even after I restart the car. After it stalls, it then hesitates and loses power, almost like it is the wrong gear and the tachometer never moves from 0 even while driving. . If i pull over and then restart it after just a couple of minutes, the problem clears up. No more hesitation, the tachometer reads the RPM, etc. The mechanic can’t find anything wrong with it. Did a complete computer scan of something like 11 systems and no problems are indicated. HELP. I love this car and pray it isn’t something fatal. 
Sounds like a bad crankshaft position sensor (aka. crank sensor), they can fail intermittently without setting a code…
It is normal for the tachometer to read 0 rpms and a vehicle to loose power when an engine stalls, as it is no longer running…
1 Like
They just replaced the crankshaft position indicators. Maybe they got a bad one. However the tachometer just go to 0 when it stalls. It never starts to read again until i restart it a few times and the engine runs smoothly. Are the crankshaft position indicators inter-related to the tachometer?
But thank you for your quick response
1 Like
Yes the crank sensor (normally) signals the tachometer (speaking loosely)…
Depending on where the shop bought the part from and if a quality part was bought it could be a new bad part… AutoZone for an example has very low quality parts with a higher than normal/average failure rate, same with cheaper lines at other parts houses…
What needs to happen is the mechanic needs a scanner able to read Live Data to see what signal is dropping out when the vehicle stalls out, A pro level should be able to record this and freeze frame it for the mechanic to be able to read it, once the the sensor (possible crank sensor as an example) drops out and is confirmed is the issue, then you start running test, like resistance/ohm checks, checking for loose/corroded/bad connections, signal in/out of the ECM and so forth…
So if you are unable to do this, then you will have to find a more advanced repair shop competent in doing higher level diagnostics, you will pay for their time and knowledge… You might also just have to leave the vehicle with the shop for a while…
Sometimes, you have to find and use an automotive electrical specialty shop… Depending on the level of technician at the dealership, they maybe required…
Their are quite a few possible component’s that could be causing your issue, the crank sensor is just the most common of many…
1 Like
Tester