Last night, reset PCM by unplugging PCM bat and PCM ignit fuses, waited 5 minutes, replaced fuses and started engine with trailblazer running fine until this evening when it suddenly lost power and cut off. This was repeated a couple of times and seems to be recovering. Can there still be a problem with the PCM recovering and or needing reprogrammed?

chevy 2002 suburban 1500 or 2500?
I will guess 1500
GEN 9
engines. 4.8,5.3,5.7, 6.0, and 8.1
check fuse first, all.
then unplug battery NEG LUG cable for 1 hour,
this unplug causes all CAPS inside all PCM/TCM/BCM brains
and all chips that go to latchup mode, (to save them selves form events like this) to discharge below 0.3vdc, <<
and will cause them all to do a simple auto reset.
do not guess parts, leave the fuel for last
spark is first,( no engine told) but if gas engine, spark is first.
Hard logic PCM, if spark fails, the PCM cuts fuel
so paying with fuel parts first is wrong.
spark good to all spark plugs ,not only 1.
all.
the fuse for OBD2 scan tool on pin 16 there must be good or the
scan tool will not work at all.
then if pin 16 is 12vdc, FUSE LABELED CIGAR,RUNS PIN 16 !!!!
15AMP FUSE
IF FUSE GOOD then comm errors means PCM is dead or asleep like I told above. CAN I ASSUME THIS TOOL WORKED THIS CAR BEFORE?
if super dead still unplug the battery NEG lug over night.
save your cash, get the DC power to 0vdc, so the PCm can do its HARD reset.
sorry for you lightning hit, that can do lots of damage.
but the rubber tires on car may have saved it from true damage.

best wishes , and do post back with results.

PS:
key fuses are :PCM
ECM 1, ECM-b, IGN0, AND IGN1., ( < FUSE FOR TB TWB)
INJ- A OR B.
ENG-1
ABOVE IS WILD LIST OF 5 ENGINE FUSE NAMES .
NO ENGINE TOLD.

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.

Here you go have fun...
For those vehicles that use a BCM, the BCM can learn the resistance value of the existing key by using the relearn process. In order for the vehicle to start, the BCM (as well as the Passkey module in other vehicles) must identify the resistor pellet in the key, then the BCM sends a password to the PCM. If this password matches the password stored in the PCM, the system enables fuel delivery. So you can see that if either the BCM or PCM are replaced, a relearn procedure is necessary. This same relearn procedure can be used if an ignition key with a different resistance value is used to replace the existing key. Before beginning the relearn, make sure there is a fully charged battery in the vehicle, and both the BCM and PCM are properly powered up and in communication with each other. Now you're ready to initiate the relearn procedure.

1. First, insert the ignition key and turn the ignition switch to the "On" position (Do not start the engine). Leave the switch on for 11 minutes. The security light may flash or be on steady during this 11 minute period. Make sure the light is no longer on or flashing before proceeding to #2 .
2. Turn the ignition switch off for 30 seconds.
3. Turn the ignition switch to the "On" position (as in step #1) for 11 minutes again.
4. Turn the ignition switch off for another 30 seconds.
5. Turn the ignition switch to the "On" position for 11 minutes a third time.
6. Turn the ignition switch off for 30 seconds one final time.
7. Turn the ignition switch to the "On" position one final time and wait 30 seconds.
8. Attempt to start the engine. If the engine starts and runs normally, the relearn is complete. If the engine does not start, check for trouble codes and address them before attempting the relearn procedure again.
Sorry kinda long but it is what it is.
Have a good one.

P1607 means "powertrain control module (PCM) internal circuit malfunction". According to the factory service manual, a low battery condition can cause this. This code can also pop up after the battery has been jump started.

You need to reset the PCM. To do this, turn the ignition switch off. Remove the No. 13 fuse (7.5Amp) from the passenger's under dash fuse/relay box for at least 10 seconds. Put the fuse back in. That should complete the reset.

Now to check again for the code: turn the ignition switch to on (not start.) Wait 30 seconds. If the check engine light stays OFF, turn the ignition switch off and wait 10 seconds. Turn the ignition switch back to on (not start). Wait 10 seconds. If the check engine light stays OFF, you had an intermittent fault and it has now been reset--everything is fine. If the check engine light comes back on during these checks, have the code that set read out. If the code is P1607 again, then you may have to have the PCM tested at the dealership for an internal fault.

Do you get a check engine light? If so, read the codes with a scanner and chase down the clues. Does the PCM match the car and engine? Was the original engine a 3.8L? 5 to 10 minutes is not very long for an engine to cool down appreciably. Hopefully, the PCM codes will indicate whether the missing problem is fuel or ignition related.

new battier and check fuses

Here is what you do, but only when the SECURITY light flashes - if it is always ON or OFF it's no use.
Turn the key in the ignition to ON.
Wait for exactly 10 minutes ( SECURITY light will flash for 10 minutes and then stay on SOLID)
Turn the key to OFF
Wait 5 seconds.
Turn the key in the ignition to ON.
Wait for exactly 10 minutes.
Turn the key to OFF
Wait 5 seconds.
Turn the key in the ignition to ON.
Wait for exactly 10 minutes.
Turn the ignition OFF.

Start the car normally.
It has relearnt the keycode and you're good to go.
NOTICE - it takes 30 minutes to relearn, that's THREE cycles of ON - 10 minutes - OFF.

Good luck.

Chevrolet 2003 TrailBlazer

For a digital air flow system try resetting the HVAC unit. Either take out the fuse for the HVAC module or disconnect the battery for 5 or 10 minutes. Reconnect battery or replace fuse. Turn the ignition to ON and DO NOT STARTor ATTEMPT to START ENGINE !!. You should hear the actuators, motors etc resetting. This should take about 2 minutes . Then you can start engine. If this does not work, you may have a bad actuator under the dash.

Check the wires to the distributer or to the modules could be poor or no conection. If you can turn the car over but no spark it's probably something to do with ignition, distributer, module, or wiring to the ignition.

VERY SIMPLE
1. Turn key to the "on" position but don't start car
2. Pull the PCM BAT and PCM IGN fuses in engine compartment
3. Wait approximately 5 minutes
4. Turn ignition off
5. Replace fuses
6. Start the car and the make sure the light has went off.
then check to see if your gas cap is on right. If this light comes on again then it is time for the dealer. If you can't find them fuses then just disconnect the battery for five minutes reconnect the battery and when you start the truck the light should be out. just let it idle for 2 minutes with no heater or radio on. and you set. I hope this helps you.