Help with PO500 Code/No speedo, or tach

i call it TAP THERAPY, works on a lot of things including EVAP purge valve

 

If the tach is not working either this points to a power problem at the cluster. The cluster (and maybe specifically the speedometer) generates an analog speed signal and turns it into a square digital wave which gets sent to the ECU. If ECU doesn't receive it then P0500 code.

The tachometer is part of the ignition circuit and shouldn't be related to the P0500 speed sensor code.

It sounds like the cluster is missing one of the power wires or ground wires. I'm not sure if a fuse would account for both speedometer and tach not working but the other gauges still working.

 

Around here we call it Percussive Maintenance but I think it's probably the same thing.


There's also a 20 lb sledgehammer in the corner, it's labelled "Medium Adjustment Tool"

 

Also, here's a potentially relevant wiring diagram. I don't think it's a fuse. Looks to me like a bad connection from the ECM. Maybe.

 

I did! Well inadvertently... I whacked it with a hammer a few times to break the threads loose and then found out that since I lived in the middle of nowhere at the time I would be waiting over a week to get a new one. Popped it back in, reset the ECU and the code never came back.

 

Very interesting, thank you. I will add that to my list of things to check and would explain why I lost both gauges at the same time. I'm hoping it is just a power/ground wire that corroded or shook free and I don't need a new cluster or ECU.

 

I'm having the same spedo and tach issue everything else works great but when my spedometer was going out the needle was jumping around and just died. any ideas?

 

Sounds like a loose ground wire

 

Same issue with my 96. Hoping you figure it out. Ill be looking into mine soon.

 

Do you know where that wire would be?

 

Looks like ground point ID on my 2000, behind the left kick panel.

 

I have been scouring the internet for this. You are a God thank you. I have been having the same issue as this guy. Could not find that schematic for the life of me. Thank you.