02 tach not working.

[bigdog9191999]

there are many threads, but not seeing my issue yet. in my 02 suburban I have no tach readings whatsoever. I swapped stepper with a known working unit, still nothing, so swapped the whole cluster assuming maybe a bad board, still nada. I have a third working cluster I intend to try just because but I am sure it will not work either. I can plug in obd2 and I get a reading there, so I know the sensors are working, any tips on how to chase down the lack of signal to the cluster? everything else works fine.


I am pretty proficient, I just recently fixed the cluster in my 03 Tahoe, ( was all dead, but illumination, and indicators) found a couple bad joints and got it all soldered back up and all working correctly again.

 

[Mechanic421]

You need a wiring diagram to chase the circuit.

 

[PNWYukon]

The IPC uses the engine speed signal circuit - 2 pulses/engine revolution - from the PCM in order to calculate the engine speed.

The tachometer defaults to 0 RPM if a malfunction in the engine speed signal circuit exists.

 

[bigdog9191999]

I don't think there is an issue in the circuit in general as the obd2 sees a reading ( I can hook a scanner up and see the rpm,

wondering if it goes from the obd2 up to the cluster, or t's from the cluster and comes down to the port, may be able to tap the signal from one to the other and basically make jumper to feed a signal to the cluster.

 

[live2pull]

See if you can test continuity of c2-10 to A5 white wire