I've got a 2002 XX. Everything was working fine. Then one day while doing routine maintenance - oil change and just looking everything over, I went to start the bike and the tach didn't move.
Doesn't sweep when turned on, sits at zero while bike is running. Everything else seems to work fine, just not the tach.
I believe the tach itself is fine. I fear it's the ECU that is the issue.

Anyone every experience this. Any advice on testing to figure out if it's the tach or the ECU?
Anyone what to buy an XX?

 

Nah, tach is dead. Without being connected to anything, if you apply just power + ground, it will do RPM sweep. That's a built-in self-check routine when it powers up. If it doesn't do that, it's dead.

 

Ok, so I'm assuming the tach is really just a volt meter and NOT using some kind of PWM.

So you are saying the sweep logic at startup is build into the dash circuitry, not the ECU. How can I test this?
And how can I bench test just the tach itself (without powering the entire dash)?

Really want to diagnose this. I don't like spending money just to throw parts at it.

 

I suppose you can take it apart and trace the power+gnd wires from connector to tach. Then apply power+gnd directly to it

 

Apparently the XX tach does not sweep as part of the startup diag. So this doesn't tell me anything.
The fact that the gear indicator doesn't work either has me believing that it's the ECU again.
It's plumbed inline before the gauges, so it doesn't appear to be getting a signal either.
Rumor is it's PWM and then coverted to analog. Not sure if this is done in the ECU or the dash, or what the gear indicator is expecting.
I need an oscilloscope. Still need to test the tach itself.