91 1.5L Code 1 and no start are they related?

Yesterday my check engine light came one. Through this forum I found out how to check for the code.(Thanks all). It is a code one. I reset the ECU and sure enough the light came back on today. Same code. One thing I did notice is that after the light comes on and I shut off the engine, if I immediately try to start the car, I just get a click and nothing else, the starter doesn't engage or anything. I am thinking that these two symptoms are related to the code 1. Can anybody confirm that?

Code 1=oxygen sensor. This will not cause the car to not start. It'll run rich but that's about it.

Cutting these cars on and off in short trips screws up the main fuel pump relay (ie. "main relay"). Do a search for "main relay" and read up on all the quirks. Basically, the solder points have to stay clean and connected. I never had to replace mine but admit that it did give problems sometimes. Sometimes rather embarassing, like trying to leave work at the end of an excruciatingly hot summer day.

Code 1=oxygen sensor. This will not cause the car to not start. It'll run rich but that's about it.

Cutting these cars on and off in short trips screws up the main fuel pump relay (ie. "main relay"). Do a search for "main relay" and read up on all the quirks. Basically, the solder points have to stay clean and connected. I never had to replace mine but admit that it did give problems sometimes. Sometimes rather embarassing, like trying to leave work at the end of an excruciatingly hot summer day.

If the main relay is going bad, won't it throw a code?

No, it won't throw a code, b/c it's not one of the sensors or output actuators linked to the ECU. In fact, it turns the ECU control circuit on, as well as the fuel pump.