How do I reset the PCM on a 04 chevy trailblazer

This seems to cover it. Found from here

https://www.google.com/search?q=Chevy+Trailblazer+Flash+computer+to+make+a+2006+with+24+teeth+to+work+in+my+2008+with+58+teeth

04 Trailblazer Engine Swap

https://www.trailvoy.com > ... > Engine Tunes/Mods
Jun 7, 2011 - The 08 crank has a 56 tooth reluctor wheel on it. The 08 PCM needs this signal to run. Instead of getting 58 pulses per rev, it is getting 7 ...

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I found this

Ok, do the following procedure if it does not work try it again with a new key if problem still exists the ignition switch/passlock sensor needs to be replaced then the following procedure will need to be performed again.

1. Turn key into on position with engine off.
2. Bump key into start position for a second without trying to start it and leave key in on position.
3. Leave key in on position for at least 10 minutes and security light will turn off.
4. Turn key off and wait 5 seconds.
5. Repeat steps 1-4 2 more times for a total of 3 times/30 minutes
6. Vehicle should now start.

Turn everything, all switches, off then disconnect both battery cables and leave disconnected for 30 minutes. This resets PCM to defaults. Then reconnect ( + ) first then ( - ).

Disconnect the NEGATIVE battery cable from the battery... Hold it or position to the POSITIVE battery cable for about 5 minutes. Also make sure you leave the key in the ON position (Do not have the engine running) and this will clear the memory on all computers/modules in the truck.

I’m happy to help further over the phone at https://www.6ya.com/expert/jason_00b31cc8f593773a

Check for OBD2 codes, primarily a code indicating PCM memory is corrupt. My Trailblazer at times wouldn't turn over and start. Nothing at the key. When you attempt to start the vehicle and you turn the key to the start position, the PCM sends a signal to the starter relay to start the engine. Youtube video showed a mechanic warming the PCM with a hair dryer, and it would start. Tried it on mine and it started fine. If it is the PCM, the remedy is PCM replacement. Got mine from pcmforless.com about $100.00. They had to program the new PCM with the vehicle vin number. Once installed no more problems.

5.3L Engine

The Powertrain Control Module (PCM) is located on the left front frame rail.

4.2L Engine

The Powertrain Control Module (PCM) is located in the engine compartment. It is mounted on the left side of the engine.

Sometimes the Computer [PCM] that controls the engine will loose it's memory on how you've driven it when power is removed. It should reset itself after a few miles of driving.

PCM is what control's all of your engine sensor's, there's no repair for the PCM, but to replace.

easyiest way to find info about any car you own is clymers books.helps to see if its something you really want to do yourself.

2004 Chevy Trailblazer radio won't eject CD. Push the eject button and the thing just clicks and says "check CD" . Tried bulletin 04--8-44-020C (fuse removal and reinstall) didn't work. Any other suggestions before going to dealer?