02 monte carlo was running fine then tcs light came on and service engine started flashing turned car off now won't turn over and don't hear fuel pump come on. I jumped the starter and it cranked but would not fire. Checked all fuses and relays everything checked out, have full power throughout the car (radio, Windows, ECT...) Have limited communication with ecu idk what is going on. Thinking security but tried resting it but no success

 

What year trim package is your car?

Gen 5's use a "PassKey" security system (chip in key), Gen. 6's use "Passlock" (chip in ignition lock cylinder).

Security (Theft Deterrence) problems usually give a flashing red "Security" light that is sometimes followed by a flashing orange "battery" symbol. You could try a "Security Re-learn" procedure, but a flashing check engine light is usually an indicator of some sort of "misfire" condition and may have caused the PCM (ECU) to shut down the fuel delivery to avoid engine and/or catalytic converter damage, or the PCM may be faulty. Can you scan for codes?

Here's the Security Relearn Procedure:
(Copied and Pasted from a past thread generously provided by member RickCoMatic)

1. Attempt to start the car by turning the key to the Start/Run Position.
2. Observe that the vehicle fails to start and that the security light is illuminated.
3. Release key to the 'ON/Accessory' Position. (DO NOT turn key to the 'off' position, DO NOT remove the key.)
4. Allow the vehicle to sit with the key in the 'ON/Accessory' Position for no less than 11 minutes (the security light should stop flashing, if not wait up to 3 more minutes).
5. Turn key to off position and allow the vehicle to remain in the 'OFF' position for no less than 30 seconds.
6. Repeat #1 - #5 for 3 cycles.
7. On 4th-5th attempt, car should start.

NOTE : Since this is a fairly long procedure, I would limit all electrical sources, such as disconnecting headlights, to prevent discharge of battery.

NOTE 2 : It is SAFE to wait LONGER than the allotted time, but it is not safe to wait less time. I.e. 12 minutes instead of 11 minutes should be safe; however, waiting 10 minutes instead of 11 minutes is not safe.

Properly executed, this procedure should take approximately 35 minutes to complete.

 

Limited communication with the ECU?

If everything works with the car, besides it actually firing up, many things must be checked. First, check for fuel pressure. I know you said you can't hear the pump, so you may also want to check for voltage at the fuel pump. Keep in mind, the pump only turns on for 5 seconds or so when the key is turned on, so you will probably need someone to turn the key or to check for power to the pump.

 

She is an 02 ls 3.4l I believe 6th gen. I can't pull ant codes but I can read code (binary system programming) so I still have communication to the system but unable to read trouble codes dtc. I checked for power to pump it is powered. But won't send fuel. I took it out and tested on stand alone power source and the pump works. I also tried the relearn procedure to no avail. . This one has me stumped going to start from scratch trace all wires hoping it's just security or at worst a bad pcm

 

I had the same issue, I didnt hear the fuel pump work either, but I eventually got to where I could hear the fuel pump and It still would not fire. But mine is a 2002 ss 3.8l