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Tachometer sticking

Posted: Thu Mar 07, 2019 12:02 am
by Canbrinor
Hello, sad to post here 2 days in a row but now my tachometer has acted up. It started when I started it up and it said it was idling at 2000rpm. By the time I finished driving it stated it was idling at 5000rpm. And when I turned it off the needle was stuck in the 3000rpm position. Tried tapping the gauge cluster but it's stuck. Any idea what it could be? It's like what it perceived to be "0 rpm" was slowly increasing as I drove

Re: Tachometer sticking

Posted: Sat Mar 23, 2019 12:26 pm
by Magus732
The tachometer receives a signal from the powertrain control module, or PCM, and unless I'm mistaken, the PCM receives RPM signals from the crankshaft position sensor. The crankshaft position sensor, or CKP, is mounted on the engine front cover, connected to the crankshaft via a wheel with 35 little teeth on it. It should always read RPM at a steady rate, but I couldn't tell you what the issue might be. I will say, have someone check either the CKP or the toothed trigger wheel; it might be causing the PCM to read engine speed incorrectly.