How do you change the timing chain on 2002 saturn L100?

Is the security light flashing win you are tuning it over

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/jason_f89d77a456dfee6d

Here's a link to the P0300 code and possible causes.Sounds like clogged fuel injectors. https://www.autocodes.com/p0300_saturn.html

check mass air flow sensor

well, that is a tough one. not being there, no indication of valves hitting pistons is not a very good check. if the chain jumped, it is very likely the chain guides and chain wore out from mileage or lack of maintenance. how many miles are on the vehicle?

No it will only alighn something like every 300 or so turns ,youre all ok

Coil on plug design has no distrubutor.

For the original question, we had the same issue with a Saturn L100 - the fix was installing a new BCM - (Body Control Module).

yes you do,make sure all the lines and electrical connections are disconnected before you drop the tank all the way.change the fuel filter at the same time.

The body control module (BCM) controls the operation of the horn for the security system and remote keyless entry (RKE) functions. Circuit 28 is grounded by the BCM when the horn operation is desired. Normal operation of the horn is performed by the horn switch grounding the horn relay and is not controlled by the BCM.
You don't need to take this to a dealer ,besides there are no more saturn dealers . Try a independent repair shop .
Does the cruise control light light up when you turn the cruise on ? Have you checked the fuse's ?

checked your relay ?