PCM Replacement Astro / Safari

PCM aka ECM, BCM, ECU, and VCM. How to replace the PCM on Chevrolet Astro and GMC Safari. You must flash the replacement PCM, flashing it is beyond the limits of what the average DIYer can do, buy it pre-flashed online.

[@liuj88]

KS Calibration PROM = Knock Sensor module, according to my 1999 Astro service manual.
Thanks for the Astro/Safari content. Please keep them coming.

[@nosp13]

Thank you, Noe. I wish I had seen your video beforehand,
Nevertheless I'm going back together with mine and your info was priceless I am replacing it on a 97 with 425000 miles the transmission transmission is slipping in between 3 and 4 I am sure this is the cause

[@GrievenceCapitolist]

Great content . 96 GMC safari awd Explorer 175k . I have a 94 astro work van too . I hope these technical videos catch on .

[@manuelester7420]

Please tell me what you mean by unlocking the radio. And why. And how. What will it do?
My van hasn't been able to start for 3 weeks

[@austincable]

I'm looking at possibly replacing my PCM, my issue is can't get the fuel pump to activate, if I bypass the relay the fuel pump does work, if I hotwire the relay it works, my Chilton manual indicates that the Crankshaft Position Sensor is tied to that circuit, when I inspected that I found it was soaked with engine coolant (even inside the connector), I'm assuming from my flushing the engine.
Question 1: could the Crankshaft Position Sensor have shorted and gone bad?
Question 2: could the Crankshaft P.S. being shorted damage the PCM?
Question 3: what troubleshooting steps would you take next?
Thx for your time!

[@OldSchoolNoe]

What year is your Astro van? I'd like to pullup the wiring diagram for your year. For example , the 1997, the fuel pump is not on the same circuit as the CKP Sensor.
Q1: Yes, there is a good possibility of the terminals shorting out due to the fluid. When this happens a fuse blows.
Q2: The fuse breaking is designed to protect the circuit, so most likely the PCM is ok. (Assuming the fuse blew)
Q3: I'd like the year of the van to look up the specific diagram for the fuel pump and (CKP) sensor. From there on you can look at specific fuses and test for power/ground at key points.

[@stevemarkovic9326]

So I cant just buy a new pcm from o riley and replace the old one with the new one?

[@OldSchoolNoe]

This is following the official GM service procedure. I have not tried just swapping in a PCM that I bought new or got from the junkyard. I do not recommend it but you can try and update us on what happens. I believe the vehicle would crank and not start due to the anti-theft module having an issue.

[@stevemarkovic9326]

Thanks for the response. I'm not gonna attempt it if that's the case lol

[@manuelester7420]

Hi, its me again 🥺 i live in my 98 GMC SAFARI and it shut down while driving without warning. Been stuck in a parking lot for 3 weeks and am afraid i will be homeless soon if they tow it😢.
Please listen to everything that i bought. I go through 3 distributor caps and rotors per year living in south Florida. The moisture kils the cap and rotor. I finally drilled 2 holes which is what all florida Astro/safari owners say is the fix. Only time will tell. 😢
I just installed a new distributor and the cap and rotor and spark plugs and wires and ignition coil and ingnition control module and crank position sensor and a brand new battery.
Im going to try and start it soon, but im so scared because after each part i installed, nothing happened.
The crank position sensor was the last thing i installed but haven't tried to start it yet.
My fuel pump makes the normal sound when the key is switched on and when switched back off. But as we know, just because it sounds good, doesn't necessarily mean its got enough fuel pressure to get the gas to the engine.
I haven't done any spark tests and i haven't checked fuel pressure with a gauge.
I haven't tested anything yet.
I haven't used a scan tool because i don't have one and nobody will come to me and i can't afford one.
Time is of the essence.. i don't wanna lose my van. I don't know what to test of where to start.

[@OldSchoolNoe]

Huh, I would just start it, take it from there, as for the radio comment, some of the OEM radios require a "procedure" to unlock after disconnecting the battery. I haven't run into one on these vans.