I got a 2000 gmc Jimmy no start, no spark and diagnostic computer says no link or communication from pcm. Any ideas? I did check all the fuses and the wiring to the distributor, crank sensor, ignition module and fuel pump.

Cranks but won't start an run ! Is there fuel pressure ? Is there spark ? Do you know the proper way to test for these ?
No Start Diagnostic Basics EricTheCarGuy

You have a bus communication problem. Start by checking all fuses. Next check all connectors. Specifically the pcm connectors and ground. These are located in the engine compartment on the passenger side behind air intake. I have ha 2-3 of these trucks need either a pcm or connector for open asd relay circuit issues.

Without the proper testing equipment an knowledge ( factory service info. ) You have no idea what's up . an don't have a chance of fixing this . Checking for DTC'S - diagnostic trouble codes is always the first step . Take's a professional type scan tool to read these codes. Serial data info from module incharge to PCM/ECM ,enable or disable fuel and or starter operation . Sends coded messages Your best bet , take it to a qualified repair shop . That white component is the ignition switch .
The design of the passlock™ system is to prevent the vehicle operation if the proper ignition key is not used in order to start the vehicle. The mechanical key, in normal operation, will turn the passlock™ lock cylinder. The passlock™ sensor will relay the passlock™ data to the body control module (BCM). The BCM will determine the validity of the passlock™ data. The BCM will send a code password to the vehicle/powertrain control module (VCM/PCM). When the VCM/PCM receives the correct code the VCM/PCM allows the fuel injectors to operate normally. The passlock™ system requires the VCM/PCM and the BCM to communicate the various functions in order to operate. These functions transmit over the class 2 serial data line CKT 1807. For an explanation of the class 2 serial data operation refer to Data Link Communications Circuit Description in Wiring Systems

Check the cigar fuse located in the fuse block in the drivers side fuse block ( on the end of the dash). Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

It don't love you any more!
You need to check and see if you're losing spark or fuel when it does not start.
Listen for the pump to buzz for about 2 seconds when you first turn the key on. No buzz could be relay, fuel pump or its circuit.
If it does not buzz, crank the engine for a few more seconds until you see the oil pressure go up. If it still does not have fuel then the pump or its wiriing may be bad.

No spark could be coil or ignition module or the wiring. Check for power to the coil. Auto Zone can test the ignition module for free. The old idea that when a module is bad its done is NOT true. The module can give intermitent problems. A vehicle can run with a bad module. If you have a tachometer and the vehicle runs smooth but the tach is bouncing, the module is bad.
The ignition module also send a signal to the PCM so it knows the vehicle is running and will send a pulse to the injectors.

I need more info. Does it not turn over? Does it turn over but not start? Does it try to start? It could either be electrical or a fuel problem. You have to know which. When you turn the ignition on, (when the dash lights and gauges come on), listen for the fuel pump to cycle (run), if not check the fuses and or relays. Your owner's manuel in the glove compartment should tell you which fuse it is. If the pump cycles check the pcm or ignition fuse. Then you have to go from there. If no spark to the plugs it could be a coil, crank trigger, etc.

a simple 12vdc will not due, it needs a pulse signal from the computer. a full 12vdc could fry the injectors, but the spider assemblys in them v6's are always a @$!$@ up design. i have encountered alot of them with bad pcm, or the spider.

i had the same problem and replaced the fuel pressure regulator. Cost about $45 at advance auto store or about $90 at napa auto stores. Once i replace that my truck started right yup and runs like a champ

do you have access to a scanner to check the computer , possibly the computer has gone bad .

A COMMON PROBLEM I'VE SEEN MANY TIMES IS THE CRANK SENSOR DISRUPTING COMMUNICATION WITH PCM. UNPLUG THE CRANK SENSOR AND CHECK FOR RESPONSE OF PCM. IF COMMUNICATION IS NOW POSSIBLE YOU HAVE A BAD CRANK SENSOR. IT'S A PROBLEM I'VE SEEN NUMEROUS TIMES. DOUBLE CHECK YOUR TIMING.