Tach died
#1
Racer
Thread Starter
Tach died
I did some searching and found others with a similar problem, but no obvious solution. This just happened to me today. When I start the car the tach does its sweep thing, and then drops to zero. And it stays there, even though everything else works perfectly. The car runs and drives just like it should, but apparently I can cruise at 75mph at 0rpms.
Any idea where I should start looking?
Any idea where I should start looking?
#2
Instructor
Had the same exact issue with my 2000. Checked everything CPU, Can sensor etc. Finally replaced gage cluster. Problem solved. Marc at Vettnuts is where I got new Cluster and had correct milage flashed at Chevy dealer
#3
Racer
Thread Starter
That just seems extreme, to have to replace a whole cluster because the tach died. Weird. It's strange that the initialization works and the needle sweeps, but then nothing. I'm suspecting the signal is lost somewhere, will try to dig into it this weekend.
#4
Racer
Thread Starter
Thanks for the info. The weird thing is we went for a long drive today and the tach started working again. Then it stopped again. Then it started again. So I think I have some kind of connectivity issue. I pulled the codes and here's what I've got.
10-PCM P0654 H C - Engine Speed Output Circuit, looks like the tach
28-TCS C1247 H - can't find this one
58-SDM B0090 H - can't find this one
BO-RFA C2100 H C - yep one of my tire sensors is out
BO-RFA C2105 H - interesting, this one works fine
10-PCM P0654 H C - Engine Speed Output Circuit, looks like the tach
28-TCS C1247 H - can't find this one
58-SDM B0090 H - can't find this one
BO-RFA C2100 H C - yep one of my tire sensors is out
BO-RFA C2105 H - interesting, this one works fine
#5
I had the same issue with the cluster not reading RPMs. On my car the cluster was fine, the wiring from the PCM to the cluster had an open. Had a new wire run from the PCM to the cluster to fix the issue.
If you want to look at the wiring here is the schematic.
If you want to look at the wiring here is the schematic.
Last edited by RedRiderZR1; 04-15-2018 at 12:19 AM.
#6
Drifting
I also have a tach issue. It wants to stick at lower rpms but once past 2000 rpms it works perfectly. Usually after a day or two of driving it will begin to work normally again. The HUD is showing the rpms accurately.
#7
Racer
Thread Starter
My HUD isn't working either, so I had nothing. I need to get the ambition to pull the dash pad and dig into the HUD.