Tacho stopped working

My Tacho recently stopped showing RPM. At first it would go up to about 500 rpm even at high revs now nothing at all. I was given advice that it may be the PTU module? So I changed this and no JOY? Any ideas?? By the way I have a 1990 GTO Japanese Import

This is now becoming a common problem and 99 times out of 100 it is the ptu. If you fitted a brand new ptu and it didn’t cure the problem, start looking for poor connection in the ptu plug and then the others leading to the rev counter display. If it is a faulty display, they are repairable.


Hi, I have a 91 tt jap import too with the same problem but have no idea what a PTU is or where to find it?

It sits directly under the coil pack and looks like attached picture.
If you are subscribed to this forum, you can go to Joes Gems category to buy one for more than £100 cheaper than mitsubishi price. If you still can’t locate the ptu, just go to the ‘request a video category’ and request a video that shows you how to replace the ptu.


Another possible cause for a misbehaving tachometer is that the capacitors on the circuit board in the gauge cluster can go bad (leak their electrolytic fluid). I had a tachometer that was giving false low readings and was easily fixed with 2 new capacitors and some time with a soldering iron.

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