Some more information I found out after some research:

The 1629 code happens when the PCM does not receive the correct signal from the PASS-Key II module during cranking.

If there is not a 1626 code already stored, and the PCM does not get the signal from the PASS-Key II module while cranking, the PCM will cut the fuel after 2 seconds. I know that the resistor keys and lock cylinder are OK, because if they weren't, the car wouldn't even crank over, and the security light would flash (it doesn't)

This appears to be exactly what is happening with my car. So it looks like one of the following is the cause:
1. Bad PASS-Key II module
2. Bad wiring/connections into PASS-Key II module
3. Bad wiring/connections between PASS-Key II module and PCM.
4. Bad PCM (hopefully not the problem)

Alldata has a diagnostic procedure flowsheet that I will attempt to follow and see if I can pinpoint the problem.

I will post what I find.

Warren
Cincinnati OH
95 Bonneville SE - Unrunning daily driver

An update:

Car still won't run, code 1629 still set. I put a multimeter on the fuel enable circuit from the PASS-Key II module to the PCM, and when the key is on, it is outputting about 50hz like it should. However, when the starter is running, the signal is all over the place, and after the fuel is cut and the engine stops, it is back to 50hz again.

I have checked the connections at the PASS-Key II module and at the PCM, and there is no corrosion. I also looked inside the modules, and there are no signs of corrosion (boards and connections are really clean).

Does anybody have any Ideas on what to check? If I remove the PASS-Key II module, the car won't even crank over, so I know that the key resistor/lock cylinder contacts are OK.

My next step is to build the Pass-Key Bypass/Emulator circuit to send the 50hz straight into the PCM, instead of the output from the module, and see if that cures the problem.

Thanks for any help,

Warren
Cincinnati Ohio
95 Bonneville SE

Bringing this thread back from the dead...

Immediately after my previous posts, I built a Passkey bypass/emulator circuit (info at http://fp.enter.net/~rockcrawl/passkey.html ). and sent the output into the PCM. The car started right up.

The P0321 code was now the only code, but the car still didn't upshift at WOT.

Fast forward to last week...Finally got around to looking into the WOT upshift problem. Got a reman PCM from Autozone, put the stock chip in it, and the P0321 and WOT upshift problem were gone. So I removed my Passkey bypass circuit and re-connected the stock Passkey wiring, and everything works fine, and there are NO CODES!!!

So the upshot was that a bad PCM was the source of all of my problems.

I hope this helps anybody else with this same problem.

Warren