Is the tachometer necessary?

[DeanBrantley]

Was told by dealer service dept that a non working tach on a 2005 challenger 4 TEC sc would cause ECM problems/errors and possible no start condition. Anyone know if this is BS or not?

 

[JPass]

Doesn't sound right to me. My buddy's '03 4Tec ski has a dead tach and she's been running fine for years.

 

[C9R0J0]

If the sensor is bad that is likely true, but as for the gauge itself I'd say it's BS. The gauge on my 06 is erratic at times, and has no effect on the engine performance. Of course if the sensor is dead I would expect the gauge to be as well. So the dealer is probably just explaining it wrong.

 

[JPass]

The tach signal wire comes off the ignition system somewhere. I guess you could check to see if you're getting a signal up to the gauge.