Hail Everyone,

'94 Bonniville with 3800 (I hope this is the right forum to post in.)

MIL is on, scanner says "camshaft sensor circuit malfunction".

I have replaced cam sensor, seemed an easy thing.
Magnet is in place, and is reasonably strong.
Replaced ICM.
Wires ohm good from sensor to ICM.

Will NOT run with crank sensor disconected.

Is a disparity where Tach reads about 1100rpm and scanner shows about 825rpm.

I'm guessing crank sensor issue. Any way to test this?
I'd had for it to be the ECU.

Thanks for any help or suggestions!

You really need an FSM to help troubleshoot this one.

The difference in rpm vs the tach is simply the gauge..nothing to worry about. Very normal.

Check for the harness routing, check for any plug wires laying on the ICM harness, add plastic wire loom if necessary. All these things can effect it.

That'* too much of a disparity between tach & scanner. The tach is getting a false signal, or grossly out of alignment. You need an Oscilloscope to check CKP Sensor output. Like Boosty says this one needs a FSM to troubleshoot.

Where in Washington are you?