1996 - 2002 GM OBS Truck Used Salvage Yard Vortec VCM / PCM VIN Reflash w/ Tech2 & SPS (Chevy & GMC)

In this GM Vehicle Control Module (VCM) (aka ECU aka PCM) reflash video we'll make use of a benchtop programming harness that simulates the GM Off Board Programming Adapter (OBPA) so that we can go over how to replace your Vortec engine VCM (both trucks and vans) with an used one from a salvage yard vehicle, including reprogramming the correct VIN and latest calibration software level (or of course to a new or remanufactured VCM from GM / ACDelco instead). This was the first generation of flash programmable control modules from GM used in the GMT400 era trucks, aka old body style (OBS) trucks, and they were called a VCM rather than a Powertrain Control Module (PCM).
You do NOT need this bench top programming adapter harness I'm showing to do the repair, you could perform the procedure I go over with the VCM installed in your actual vehicle instead. However, you WILL need access to a GM Tech2 scan tool as well as the associated GM TIS2000 software, or an acdelcotds.com Tech2Win subscription.
ADVICE:
Check that any replacement VCM matches your original ones service number EXACTLY!
You can ignore the 1996-97 TIS2000 error "M676: The ECU could be a service ECU !!!"
The eBay and Amazon search links below are paid links, for which I may be compensated and earn a commission, if you choose to buy the parts and tools shown in this video thru them:
Buy a VCM
It is always preferable to use a brand new or factory remanufactured GM / ACDelco VCM for service purposes, but as we showed an used one will also work. Documentation may refer to the part as an ECU or PCM. The part numbers for the Vortec V6 & V8 engine VCMs for these years fall into three groups:
Early 1996 GM 16208546 (built before 2/14/1996): ebay.us/YJHtLk
Early 96 VCM Rewiring Kit GM 12167310: ebay.us/Z3RU8r
1996 - 1997 GM 16244210: ebay.us/nyUYwt
1998 and up GM 16250279 (also 09366810, 09355699): ebay.us/A6PZVh and amzn.to/3tUSdXh
Buy the GM Service Manual
If you are looking for the 98 GM C/K service manual: ebay.us/Vkbhwi
Buy a Tech2
If you are looking for a GM Tech2 scan tool: ebay.us/xEWuoJ
Buy a Tech2 USB to DB9 Serial Port adapter
And if you need a USB adapter, the GM recommended Tripp Lite Keyspan USA-19HS can be found at: ebay.us/tAWnY5 or at amzn.to/2GEDwE4
WARNING: When performing SPS operations in the actual vehicle, pay very close attention to the service manual instructions around power cabling and battery readiness as a power fluctuation during an SPS programming procedure can permanently damage any controller module. GM recommends use of their EL-49642 SPS Programming Support Tool (Midtronics PSC-550S) attached to the battery to avoid this. You can also jumper cable another battery to mitigate this risk. But do NOT attempt to use a battery charger for this purpose though.
NOTE: TIS2000 was deprecated by GM in early 2008, but was once the primary Techline Information System (TIS) approach delivered to dealers via DVD media. Today we would use the subscription based TIS2Web as part of the ACDelco TDS server (www.acdelcotds.com) based offering to accomplish many of the same tasks, although the Off-Board Programming Adapter (OBPA) path shown in this video is no longer supported or offered by TIS2Web.
NOTE: be sure your USB to serial adapter device driver is configured for 115200 speed on Windows using Device Manager and that you set the COM port it is assigned to within TIS2000 for communication to be successful. GM recommends the Tripp Lite Keyspan USA-19HS adapter (USB to DB9 serial).
And if I've saved you some $$ here, consider some coins for the coffee tip-jar! ko-fi.com/drshock
1996 1997 1998 1999 2000 2001 2002
Astro Safari Express Savana Tahoe Blazer Suburban Yukon Escalade Silverado Sierra Cheyenne Sonoma Bravada Jimmy S10
Chapters
0:00 - VCM Location & Identification
3:50 - Removal from the vehicle
7:26 - Bench top wiring harness
14:20 - VCM Visual Inspection
15:18 - Knock Sensor Calibration Module Transfer
19:10 - 1996-97 VCM Programming
43:44 - 1998+ VCM Programming
58:10 - VCM Relearn Procedures
#drshock #chevytrucks #obstrucks #cheyenne
Disclaimer: DrShock, the alias for the human content creator for this KZbin channel, is not responsible for any damages, injuries, losses, or liabilities associated with any repairs, upgrades, or maintenance performed on yours, or any other, vehicle whatsoever. No warranty, express or implied, is made as to the accuracy or completeness of any information provided within this channel. Viewing and using the “as-is" information of this channel is totally at your own risk. Always wear personal protection equipment and follow appropriate vehicle manufacturer service manual guidelines with original manufacturer parts only when performing any repairs, upgrades, or maintenance upon any vehicle.

[@shelstone66]

Great video bro. Have a 97 Yukon since 08 I don't think I've ever need to have mine changed. This is a great just in case watch

[@stevenbowles2068]

I got 40 trouble codes from pcm! Too bad im going to have to get a pcm and get it flashed. Wish it was plug in and go😭Thank you for this video🙌🏾

[@mikemunoz5051]

I am not lazy just need some direction and pointers to find the specific exact information for my vehicle without all the excess I dont need. Like certified repair manuals , how to locate and know for a fact that finding and locating manufacturers and specific data needed to fix, maintain and repair my vehicle like the auto dealers do. Thank u and look forward to th challenges ahead.

[@danielpaulson786]

Dude,all I can say is thank you and make more videos.

[@DrShock]

Thanks, there's a few hundred out there already so check out my channel further if interested.

[@stevecockerham]

Great video. Was having VCM communicating w/scanner issue. Made a copy of your connectors from Data Link and VCM and checked for all. C3 White pin 21 ORN #440 (battery feed) had no 12 VDC, messed the wire and had 12 VDC. Bad connection between wire and contact. Gotta get a pin extractor and contact now. Thanks so much!!

[@DrShock]

Thanks, glad it helped out.

[@user-fn5vo1wy3x]

I have a 2000 Chevy ZR2 S10 that won't charge the battery. Brand new battery, brand new alternator bench tested, L wire continuity to PCM from alternator good, all fuses good and all grounds good. Does the PCM talk to the alternator to charge the battery. I am at a loss to why it won't charge. Your video is fantastic., so interesting to see have the PCM is flashed. Thanks for showing it.

[@rrbdragracing7501]

Morning everybody, 97 s10 2.2 liter, my problem is when I turn on the switch of the a/c nothing came on and the abs light came up, I disconnect the blower motor and the compressor quick on or I disconnect the blower resistor the compressor quick on, 🤔

[@DanMcD80]

411 swap is the way to go if you want to be able to tune engine & trans

[@b.c4066]

The later black box can be tuned, jet dst, hptuners, and of course the gm factory stuff he mentions here allows them to be tuned just as well as the 411. Just not as user friendly and common as the 411.

[@jefferyyancey1616]

❤l explain that plz

[@2001zrt800]

Does anyone know how to rewire 97 ecm to 98? Specific wire moves

[@LinuxWiz1983]

@@2001zrt800 I would like to know this as well

[@vecinomio]

Very good video Thank you. My 99 express 4.3 just died today I just check the signals from the ckp & cmp spark and fuel pressure all are ok seems like ECM fail because the injectors pulse are not synchronizing, any idea here ?

[@jorgeguzman372]

Have you checked if all your injector work?? Cause i tried my truck and I have 1 n 8 not working I have ground and 12v to the connector and the injectors are new so 1 n 8 is not working for some reason

[@repeatman]

Is there a way to delete the "Security" function or make it to where the moduel does not look for the anti theft moduel? Want to do this on a 1998 chevy tahoe.

[@DrShock]

Nope, part of the VCM firmware (built in programming).

[@scotttucker4075]

Maybe I missed it, But just wondering if you ever ran across a problem with Scan to unable to communicate with VCM on GM specific but will communicate with VCM in OBD generic,, I assume all communication comes from black c3 connector Pin 8 class two data line, this is on a '98 c 1500 built date 1 of 98, But strangely this VCM also has the C5 connector that I never seen on the 98, owner said he had it since new and appears to be factory wiring,, and back probing to Pin 2 on DLC connector to an oscilloscope, It does show a 7 volt to ground square wave,, I'm thinking that scan tool using another way of communicating with VCM,, The truck runs fine without a problem and the only reason why I was doing a full scan on truck was due to anti-lock brake light was on, that problem was fixed with the new brake control module The problem still exist with unable to communicate with VCM but now can communicate with brake control module and anti-theft module Just wondering if you had this trouble or gotten this deep into the communications of the VCM

[@DrShock]

For these OBS trucks I only use the GM Tech2 type tool, no aftermarket scan tools and not even an MDI. So I can't say I've come across this kind of comms situation before. Typically if there was a comms issue with the VCM I would expect some module somewhere to throw a "U" type DTC, but not always.

[@MechanaholicsCreations]

I have a question. I'm trying to find the 5 volt reference for the tp sensor and on Mitchell, it says gray c3 connector on terminal 12 but on the pcm there's only red, white, black, and blue. Is the white the grey connector?

[@DrShock]

Yeah the white/grey/neutral/clear terms are typically interchangeable on these 90s VCMs.

[@MechanaholicsCreations]

@@DrShock are the 24 and 32 pin harness connector diagrams numbered the same? Because what it shows me isn't adding up for the "grey" connector.

[@DrShock]

@@MechanaholicsCreations Not sure about what you were asking with this question, but the wiring will differ from early 1996 and others pinout wise. While I tried to show all the VCM connectors and their pinouts for both design in the video, if you don't see a specific one you are looking for you may still find it in the GM service manual.

[@michaelvita8]

So if you swap ecm c/m with a used one you send ur vin in they reprogram it to ur vin do you need to use a tech 2 to do any relearn for 1997 c1500 or if it's been vin programed it's a simple plug in play ?

[@DrShock]

If you are buying an used remanufactured VCM or PCM from an online service, or sending one in for reconditioning, they may offer to take care of everything such that it is plug and play for you. But ask them your questions before you buy. Typically a remanufactured module, even if you buy it from GM ACDelco, DOES still need to have the scan tool for setup. But some outfits may offer a more customized programming service at the EEPROM chip level.

[@lemoncake9597]

So if I have a pcm from the same year and engine package can I swap them without having the tech 2 scanner? The only thing I know that would be different in the trucks is the gear ratio. But I swapped the axles front and rear from that truck into mine.

[@DrShock]

You would have to use the scan tool to learn the VIN of the vehicle to the VCM memory. There is also having the VCM learn the security code from the passlock module. If the security isn't learned, the security lamp on the instrument cluster will illuminate, and the engine will fail to start.

[@mikemunoz5051]

I am swapping out my black box (old ecm) with the 0411 and can use and need help doing that. I got ripped off by mechanics and legit auto repair places. And like to fix up older chevys.

[@GCxRenegade]

Can I swap a matching ECM from a good running truck into mine, without flashing, just to see if mine runs better and fixes my problems?

[@DrShock]

What you can run into is that the anti-theft system with the ignition will have a mismatch in addition to the VIN, so will prevent the vehicle from starting. You'd make better use of your time I'd suggest, is to determine what is specifically causing you to suspect the VCM (for these model years GM called it that) and confirm you need to replace it. These computers are super rugged, even after over two decades they rarely fail.

[@andreporter9881]

I have a question similar to the one Renegade asked. Is it possible to swap the ECM from 97 into my 96? The reason being, I blew a ecm fuse due to a wire melting. After repairing the wire, replacing the fuse, the truck misfires horribly, (p0300) and I have a mass air flow sensor low input (p0102) code. These codes did not exist before the fuse blew, as the truck ran alot better than it does now. Thanks in advance.

[@DrShock]

The biggest challenge with the 1996 is that the early VCMs there were wired differently than later model years. You'll want to see what current part number you have in the truck, to determine if that wiring difference is there. If you have the earlier one, you'll have to apply the service bulletin changes first. The later 96 and the 97 use the same VCM so no problem there. There would be a problem trying to use a 1998 and higher one though. The part numbers, and links to find, for all of them are in the description.

[@gregwolf3296]

@@DrShock Excellent video, thank you. I bought a replacement 96 ECM from Flagship with the newer numbers, can it be swapped straight in place of the older 96 ECM?

[@DrShock]

@@gregwolf3296 Those folks rebuild VCMs, so they might rework the contents from what the outside labels/numbers are as part of the refurbishing they do. So it would be best to ask them directly based on what they sold you. But in general, there are three designs that are not interchangeable hat you have to be concerned with. The early 1996 VCM harness pinout being unique, then the later 1996-97, and then the 98 and up. Just those three.

[@jorgeguzman372]

Hey did you ever got that fix?? Cause mine runs but has a misfire o already changed everything do I have to get a new ecm and get it flash??

[@khalilhinton7336]

You may not know but I'm just asking. Where the jumperwire goes in pin 26 broke off. Is it safe to put it in a different numbered slot

[@DrShock]

The GM service bulletin instructions I show at 22:17 require pin 26 on the RED connector (R26) to be rerouted to pin 18 on the WHITE connector (W18). Pin 26 is populated in the wiring harness and active to that same pin on the VCM, so you have to repair what became damaged there. I don't recall if an adjacent pin cavity in the RED connector is empty to relocate this pin but I am inferring this is what you're asking. I'm reading your _different numbered slot_ to be referring to an adjacent pin cavity in the connector. You _cannot_ just move the wire in the connector as it has to make a connection to the VCM pin too. But as long as you connect what _originally_ was pin 26 in the RED connector/VCM, to what was _orginally_ pin 18 in the WHITE connector/VCM you'll be able to make a repair of what you had break here. Now on the other hand, if the pin on the VCM side broke, it's toast and you'll have to replace the VCM. Hope that helps.

[@Thewindingstairs747]

Do you have a video or a diagram of your bench wiring harness? The highlighted pins from the service manual pages you show in this video, I’m assuming, are the only pins I would need to make my own.?.?.! Right?

[@DrShock]

This vid is it. And yep, that's the reason I took the time to go over those connections. ;-)

[@Thewindingstairs747]

@@DrShock I can’t tell by looking at still shots of this videos which wires I need to put together. Can I get a little help with that please? Thank you in advance T. O.

[@DrShock]

You're looking to bring together all the grounds, and all the battery positive voltages. These you'll have to supply power to. The ignition voltages need to be switched, so they'll run thru a switch before being connected to the power supply voltage. Finally, the communications bus lines are all brought together to recreate the network. Now I do mention exactly this starting at 7:28. But then I do show the individual pins/lines where these are found at 8:41 _highlighted in yellow only_ for the bench setup. Of course the connector pinout varies from early VCMs and later VCMs, which makes the wiring unique to the year(s) you're working on. But the bottom line is tie the same lines together (i.e., power, grounds, network) and then connect in the switch for ignition power feeds, between the DLC connector and the individual VCM connectors.

[@nauju1998]

Can you turn off the pass lock for the 98 and up trucks with this method?

[@DrShock]

There's a separate module for the security functionality (passlock module). The VCM needs the correct VIN set (what this video is about) but the security lamp on the dash is controlled by the other module, not the VCM.

[@b.c4066]

So you offer this service? I'd like to use the engine and ECU from a 2000 GMC Sierra sl classic k3500 in a 1997 c1500 and have it setup right so anyone can plug into it and scan it. Aside from turning off the downstream O2 sensor and changing the evap to match the c1500 tank volume, and 4wd features changed to 2wd it would be completely factory spec.

[@DrShock]

Sorry, no not a business. Just sharing the how-to info.

[@gregwolf3296]

Can you post links to the service bulletins mentioned in your video please. Thanks!

[@DrShock]

No can do, these are available by paid subscription only. Go to www.acdelcotds.com, and you can subscribe to GM service information for your model year to view and print them out though.

[@gregwolf3296]

@@DrShock Just wanted to follow up on my questions and your thoughtful answers above. I made the wiring changes based on the TSB as they weren't done. It didn't seem to change anything as far as how the transmission, which was recently rebuilt, ran, and everything looked good on the Tech-2 both before and after. Regarding the ECM on the truck, I had ordered up an ECM from Flagship One previously and they must have located another early one based on my VIN because it also works perfectly, not surprisingly as it has been programmed to my trucks specific VIN. Over the last while I've replaced all of the sensors, distributor and injectors on the truck and the truck runs wonderfully like it would from new. Looking forward to many more years of reliable use from my 7.4. Huge thanks for your channel and all the work you're showing on these trucks. I REALLY appreciate the exact details and explanations and clear video. Also great video on the TECH 2 which I purchased, very worthwhile especially where I live in Canada and shop service rates are $150-$200 an hour and frankly they aren't very good on trucks this old.

[@gregwolf3296]

@@DrShock A further comment on my post below on the TSB and the ECM from Flagship, the ECM Flagship sent does have a 16244210 label on it so as the TSB states " Corrections were made to the VCM beginning 2/14/96.The corrected VCMs are identified with service number 16244210 on the VCM identification label. I'll continue to run my original ECM and reverse the wiring back from the TSB if I need to run the new ECM in the future, even though the truck runs fine with either of them. Thanks again, great channel.

[@ismaelcarrillo3956]

Quick question. Can I saw a 97 Yukon ecm on a 97 sierra?

[@DrShock]

You would have to change the calibration (reflash) it using a Tech2 scan tool, but yeah it's the same VCM part for that year (they called them a VCM in 97 since it also controlled the transmission).

[@khalilhinton7336]

If I broke one of the white pins to connector is it safe to put my jumperwire in a different slot?

[@DrShock]

Not sure exactly what you're describing here, but it is important if you're implementing the service bulletin I went over that you jumper the exact pins described.

[@khalilhinton7336]

The vcm update on the 96 chevy computers

[@kurtrobbins2021]

Any chance you can post a link for the pin out diagram for the later ecu(97)?

[@DrShock]

That would be the GM 16244210 (late 1996 thru 1997), which is the same as the later production 1996 I showed. It's only the early 1996 ones that had the wiring defect mentioned. There's some more info like part numbers in the video description.

[@kurtrobbins2021]

@@DrShock I have, and am working on a 2000 k2500 classic. I need to back probe through the ecu to check for proper grounds. I seen that you had those pin out lists printed out to show which pin correlates to each circuit. I was hoping you had a link to those lists(diagrams) so i could print or save for my diagnosis.

[@DrShock]

These are found either in the hard copy service manual (I only have 1998 2nd edition there) or the Service Information (SI) subscription at www.acdelcotds.com. SI is where I pulled the 96-97 pages from.

[@kurtrobbins2021]

@@DrShock thank you sir!

[@bradtodosyuk8192]

just building a harness...i have orange to power...blacks to ground...ppl on black connector to ppl on dsl attached together......pink and brown??...connect together / switch to power??

[@DrShock]

The switch is used between lines for _ignition voltage_ as those only have power when you would turn the key to on, or accessory. So we use a switch to mimic that condition, as the VCM expects both constant battery power, as well as switched ignition power differently. The wiring colors may vary year to year/supplier to supplier, so I would suggest focusing on the pinout I shared instead.

[@bradtodosyuk8192]

ok... this is what I have done using your pin out ..D link..pin 2 purple to black connector pin11 purple...... black wires pins 4&5 D link to pins 17/18 grounds on gray connector......orange wire pin 16 D link to pin 21 gray connector battery power...all that is left is black connector pins13/18 brown and pink...reading what u said I assume those to wires get tied together and run to switched power...am I correct?

[@DrShock]

You only need the pins I highlighted with a yellow marker on those pages for the harness, so don't get confused by the overall explanations of 1996 differences in the pinouts. Just tie all the grounds together, and then supply your negative power supply lead to those. Tie all the serial data lines together. Tie all the battery voltage lines and one lead of the toggle switch together, and then supply your positive power supply lead to those. Finally tie all the ignition feed lines to the other lead of the toggle switch. Voila!

[@bradtodosyuk8192]

perfect...I have depinned all the useless wires out...just left with your highlighted wires...all connections are hooked up correctly. I will run the two ign feeds to switched power and carryon.....thanks DrShock🙂

[@gregwolf3296]

Quick question. Can the later 96 ECM be run in the truck once the wires have be moved and jumped per TSB 00-07-30-026?

[@DrShock]

No, as I showed in the video there are many pinout differences between the older early 96 1st design engine wiring harness and the newer 2nd design VCMs. You could, maybe, re-pin every harness connector to address these differences since I've given the information on what pin is what, but there's no guarantee that some firmware issue in the VCM would still preclude it.

[@horacioaraujo4620]

Hello, I have a 1998 k2500 that i bought about a month ago security light stays on but the truck runs normally, only thing is the fuel gauge and the temperature gauge are dead, it does look like somebody swapped out the VCM. Any idea if this is why I’m having the gauge and security issues?

[@DrShock]

There's nothing jarringly obvious in common with those symptoms. So no way to really tell without inspecting the vehicle first hand. I'd check for any DTCs first, and see where those take you on the diagnostics path. Sometimes different problems have some shared root causes, but not always.

[@MikeSmith-nu9wt]

Get your instrument cluster rebuild , security light persist check ignition wires

[@horacioaraujo4620]

It had a VCM from a 1996, what happens if I just install a 1998 VCM?

[@DrShock]

Well, a 1996 VCM is not compatible with a 1998 truck. So that could very well be part of the problems you described. The correct year VCM would still need to be programmed though.

[@juanwelding4545]

Can I put a 5.7 computer on a 454 or 7.4

[@DrShock]

All of the gasoline engines use the same VCM (same GM/ACDelco part number), but the calibration installed (the flash programming) is different from engine to engine. You need a Tech2 and TIS2000 (or a Techline Connect online subscription at www.acdelcotds.com) to reflash the calibration that matches the VIN for the engine, and update it like I show in the video.

[@rodneystansill9791]

What wires do you hook up to do the 4l80 swap to the vortec vcm

[@wilsonvalentin1738]

Hey I have a 98 Chevy 454 n my colors plugs came off I DONT know witch one is witch how can I figured it out

[@DrShock]

You can see in the video where the harness connector colors are molded into the metal VCM housing, for the OBS style truck years this video applies to. It's the same for the 4.3L, 5.0L, 5.7L and 7.4L gas engines. Only the 6.5L diesels have a different computer. Four harnesses, black/blue/red and the natural one that might be labeled either white or gray.

[@wilsonvalentin1738]

Yea but u see the color plastic on the plugs mine got taken off n now Idk witch one is witch

[@wilsonvalentin1738]

Mine is a 98 chevy 3500 with a 454 vortec gas motor it change everything

[@DrShock]

All four of the wiring harness connectors have been removed? Well in that case I'd try visiting a local LKQ type salvage yard to get a visual on how the 7.4L wiring was done to help reconnect everything. The service manual pages I show in the video would be applicable for the individual wire colors, but I expect it'd be faster to just find another truck and visually compare it. I'd probably take the harness connectors off that truck with some wire attached and splice into what you have to get back to stock.

[@ismaelcarrillo3956]

Google the wiring diagram for your pcm. Then compare the wire color patterns to your connections. All four are different

[@johnhorne5147]

Will this work on a 95 Silverado?

[@DrShock]

Only a drop in if it was a 1996 model year truck built in 1995. 1995 and prior model year trucks used the earlier PROM/memcal type computer. When OBD2 came out we got the flash programming VCMs like this video introduces. There is significant difference in the engine wiring harnesses in the pre and post era trucks here, I don't usually see this being attempted without swapping in a later engine as well. You'll need all the sensors that the later computers are looking for, for example.

[@ryan8456]

Do you sell the bench harness ?

[@DrShock]

No, I do not.

[@alexgo1034]

This TSB for early 96 PCM restores ground between halves of PCM (inside they connected by big spiked contact ) -this ground bridge corrodes . I simply soldered halves by thick wire. No need external wiring mess

[@paulhutchison8689]

I need your help ! Can I send you an ECM out of my 1998 cheyanne C/k 2500 4x4 pickup and you work your magic and send it back?

[@selrahc2061]

Black bear in Idaho does the programming as biz they can reset the vin.

[@herathliyanagerathna7459]

Sr hummer h2 2003 ecm connector pin data pls tks