my 94 Fleetwood died after driving a short distance and won't start again.

First thing to do is look for any trouble codes in the PCM. Specifically code 46. This is the code that tells us the fuel enable signal, from the CCM in the trunk, has been lost. If that's what you have, see if you have any trouble codes in the CCM. If you do, address those first. Also be aware that Cadillac called the control module in the trunk the Central Control Module (CCM). But newer cataloging calls it the Body Control Module (BCM). It's just two different names for the same thing. Has your Passkey Fault light been on? If so, that's an indication that we're dealing with the fuel enable signal being lost. When that signal is lost the PCM shuts down the fuel injectors and the engine stalls. It will set a trouble code in the PCM but the service engine soon light will not come on! If you have that code in the PCM but no codes in the CCM, replace the CCM in the trunk. It's Cardone part number 78 7386. I found a rebuilt one for my 94 Fleetwood on Ebay. Do NOT buy a used one!! A used one will have the key information from the vehicle it came out of stored and will not start your vehicle. When you install a new or rebuilt module the key information is married to the CCM when you first start the engine for the life of the CCM. Hope that helps! Jim

Passkey fault light actually was on a couple times before I replaced the opti, hasn't been on since. What trouble codes should I be looking for?

In the PCM you're looking for code 46. Do you know how to pull trouble codes using the climate control panel? Jim

I was able to pull up the codes and there was no 46. I've been looking up how to decipher any codes that I may have. None of them come up 46.

Ok, I'll double check my shop manual. What codes do you have? Jim

I got the following codes: -00 00 -01 133 -03 00 -04 164 Hope this helps.

It appears that you have no trouble codes in any of the vehicle computers. Pointer 00 is the PCM. Pointer 01 is the CCM (BCM). Pointer 02 is the Climate Control System. Pointer 03 is the Airbag System. Pointer 04 is the ABS and Traction Control Systems. When you get a 00 within any of the pointers that means you have no trouble codes stored in that system's computer. The three digit numbers are fuel trim values, and other things we're not concerned with. Try spraying a little starting fluid down the throttle body. It should run a few seconds on that. If so, it's a fuel problem. Try hitting the bottom center of the gas tank a few times with a hammer. If that gets you going, the fuel pump is bad. If not, check for spark. If you have no spark check the crankshaft position sensor. Also a bad coolant temperature sensor can cause a no start condition. Hope that helps! Jim