I hope that the more experienced forum members can help me. I have been trying to solve this problem for a longer period than I wish. Intermitantly I turn the key to start the car and NOTHING. No starting, no cranking, nothing.

I get the following codes.

P1631 - Theft Deterrent System Password Incorrect
B2721 - PASS-Key Detection Circuit
B2723 - PASS-Key Detection Circuit

Last year I did not have the problem. It started this spring after I installed the battery after having it out for the winter. Since I have had new Keyes cut, cleaned the lock cylinder contact, and replaced the balance of the ignition with the contacts in it. Yesterday I took the car for a short trip, went into a store for just a few minutes, and it wouldn't crank when I came out. I fiddled with reading the code repeatedly and dressing them. After a while the car would crank and die out because the gas had been stopped. Somehow shortly after that, it cranked and started perfectly. Today I try to start it and again no crank.

Does anyone have any suggested as to what may be wrong? I read the repair manual it it keeps suggesting scanner reading and testing, but I don't have a test scanner. Does anyone have any suggestion?

Also, is there an affordable scanner / tester the I can purchase?

Gary

 

I would be replacing the ignition switch.

The contacts in the switch can be pretty tricky.
Sometimes cleaning is not enough.
They get bent, and fail to make contact.

What you are experiencing, I did about 3 months ago.
Replaced starter, battery, and still wouldn't turn over.
Replaced the ignition switch, and never had a problem starting again.

One other thing to think about, if your Vette is an automatic.
There is a tube connected to the back of the ignition that goes to the transmission.
If it isn't connected tightly to the ignition switch, the car won't start.
You have to turn the key to the on position,and wiggle the ignition switch till you can feel the tube seating into the ignition switch.

Bob.

 

I have replaced the ignition switch, and the cable you mention is the shift lever lock. Both are ok. I suspect there is a bad wire connection somewhere that I need to locate, but electrical issues are not my favorite thing.

Thanks for the suggestions though. Both are good ones.

Gary

 

Mine was the starter. It used to do it once and a while, then while I was replacing the belts, I had the AC belt jump off twice. So the last time I got it on, I was in the driveway bumping the motor over to make sure the belt stayed on and it just stopped.

I read a bunch about the ignition and other things, decided to just bite the bullet. I got a cheap one off Amazon for less than $50. It was sort of a bitch, but it worked.

Things I learned along the way...

To drop the H pipe:

Remove/loosen exhaust manifold nuts (I left the bottom ones on, just loose)
Remove bolts from crossbeam
Remove the bolts from rear hangers (those were a pain)
Remove rear exhaust bolts and drop end of the h pipe down
Pop the last 2 wire clips on either side of the exhaust sensors
Remove the last front nuts and drop the pipe, careful of the sensor wires

I left the sensors plugged in and just laid the pipe on the ground until I was done. Other than the issues I had with the plastic flywheel cover, it was a pretty easy job.