1998 - 2002 GM OBS Truck Crank No Start EVO Passlock Module Diagnosis Repair U1000 DTC (Chevy & GMC)

In this video we will be going thru a crank no start situation with a U1000 DTC and the Security lamp lit on the instrument cluster. This is a very specific failure ultimately tied to the EVO/Passlock Module. We go thru how to isolate the problem to this particular EVO Passlock module, then how to diagnose whether the problem is in the wiring harness or the EVO Passlock module itself. Finally we show how to replace and reprogram the EVO/Passlock module to complete the DTC U1000 repair and allow the engine to start. The U1000 is a class II communications error DTC.
The truck illustrated is a 1999 Chevrolet K1500 Suburban LT, but the procedure will be the same for any 1998 thru 2002 OBS truck or SUV. Chevrolet, Cadillac, GMC, and Holden for Cheyenne, Escalade, Silverado, Tahoe, Yukon, Suburban, Sierra, and W/T trucks across C1500, K1500, C2500, K2500, C3500, and K3500 ratings. Fitment for model year 2000 is limited to Cadillac Escalade, and Chevrolet Tahoe Limited/Z71. The 3500HD for models years 2001 and 2002 would also be applicable for this repair video.
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:
EVO Passlock module GM 19352769 (supersedes 16264965) for 6.5L diesels and all 2500/3500 trucks and SUVs: ebay.us/tj6gmr or amzn.to/3G8K2iV
EVO Passlock module GM 19352768 (supersedes 16264955) for gasoline 1500 trucks and SUVs: ebay.us/6y6pVF or amzn.to/3Tw6p4L
Hardcopy GM factory service manual for these years: ebay.us/JoWX03
And if I've saved you some $$ here, consider some coins for the coffee tip-jar! ko-fi.com/drshock
1998 1999 2000 2001 2002
Chapters:
0:00 - Problem overview
1:08 - Determining a likely root cause
1:47 - Removing the EVO/Passlock module
5:05 - Service manual diagnostic information
8:51 - Locating the EVO/Passlock module harness
10:29 - Running EVO/Passlock module diagnostics
17:31 - Testing replacement EVO/Passlock module
17:58 - EVO/Passlock module relearn procedure
23:55 - EVO/Passlock module tear down
26:55 - Trim reassembly
#drshock #obstruck #obstrucks
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.

[@michaelhewitt-dt9pz]

This is so thorough. Been having trouble understanding why the PASSLOCK system would not let 1998 GMC Sierra 1500 stay running. Turns out no battery Power on pin #8 with reference ground pin #1. Installed umper wire instead of buying a new harness, and wow, truck started right away. Thank you sir!

[@nestorroman2694]

Excellent information Sir! Bravo 👏! I can tell you are highly educated. Please keep teaching us. Just Subscribed! 👍

[@crautoguy8384]

Thank you so much Have done this diagnostic in the past But do not currently have Diagnostic Theory and wiring diagram accessibility I have bypassed his sister's pad locks before ll 😢 it's been a long time this video was exactly everything I needed to know from an actual Professional Great video thank you 😊

[@eablau]

As always in your presentations: excellent methodology in troubleshooting the problem. Learned about your inexpensive oscilloscope.

[@lonniedillon6046]

One of the best videos I have ever watched. Excellent in every way.

[@mikemackey8888]

Very informal thanks, one of the best ive seen. 5 stars Dr. Shock...

[@rudygingerich5711]

Thank you! Very helpful

[@calvinpochinko4277]

HP Tuners software?.. I understand that if someone near you has HP tuners you can go inside the ECU and turn the switch off for the passlock or Vats.. I believe it would require 2 HP tuner tokens and whatever the shop wants to charge you to do the job but once you have HP tuners it is locked into your serial number on your computer permanently and if you are smart enough I believe you can buy a dongle to plug into your laptop and do it yourself.. it's a credit based system... if you're really need security you can always put in a hidden switch for the fuel pump.. I believe HP tuners will do 1998 to 2000 as well as numerous other vehicles.. this is a great tutorial but this is my second vehicle that the vats has give me a problem.. one was a 1998 k3500 and now my 1999 Suburban k2500 is not starting on occasion and I have to do the 10 minute wait.. I'm actually going to buy another truck that is a 98 3/4 ton that is having the same problem and apparently the dealer said the body control module is toast.. I do have two parts trucks luckily and maybe I can use those spare bcms to buy a few dead trucks😃

[@arguswil]

Guess I have to go back to the junkyard 😂

[@ezbdaniels]

Awesome video 🤘

[@arguswil]

Amazing vidoe 🎉

[@lanelukefahr1184]

I am very impressed with the video very informative. I do have a question though is there any possible way to just eliminate this anti theft system to make these motors run without this system?

[@privateshooter]

I have a 97 Chevy Tahoe 4x4 5.7 which I recently installed a HT383E crate engine. It was a plug and play but throughout the months we had to change MAF, Injectors, Distributor to get it working good. It was recommended that I TUNE the engine for fuel and shifting performance. I have a 99 Tahoe 4x4 ECM installed and vehicle would not stay on. Is it because the 99 ECM has the Passlock feature? My dashboard on the 97 does not display security? Any guidance is appreciated!

[@johnhollyfield1957]

Thanks!

[@Pdubforever1]

I'm currently dealing with this issue. will be doing pwr & gnd checks in the morning. if it is the module, will I still be able to bypass the system?

[@hunterburris7958]

Im having the same problem 2000 5.7 3500 chevy the only difference is mine is flashing it will turn over and run for a quick second and security light is flashing

[@mitchells.1775]

Where can I find that service manual??

[@DrShock]

Should be a search link in the video description

[@user-ym5hs5hf3i]

I tested pin a5 to pin b1 no volts and no OL on resistor. I unplugged the ignition switch module and same thing. I saw on your video the book said repair the ground on CKT 812 I trying to figure what it that part

[@DrShock]

You'll need the service manual to trace that path, you can _rent_ access online for a weekend at www.acdelcotds.com under the SI (Service Information) subscription section. What they are saying on that page is the test result implies the ground path is either broken (broken or corroded wiring) or missing at the frame attach point (ground strap or bolt broken or missing).

[@billrobinson9308]

Excellent video much appreciated… Quick question is the used module the only option are there new ones to be had ??

[@DrShock]

Thanks. Discontinued by GM long ago. Maybe New Old Stock (NOS) that could show up on eBay once or twice a year, but that would be it. Used and non-OEM rebuilt only nowadays, links in the description for those.

[@roadblock952]

Yes you help me out

[@user-fe3cq1uc1x]

Having kind of the same problem except this was deliberately as I have 2 trucks a 99 c1500 5.0 and a 2000 c2500 out of the clear blue they both developed the same issue funny thing is the 1500 I haven't driven for a little while. Problem no start fuel gauge spins a circle and seat belt light flashes security light comes on and goes out. Any advise on this issue would be greatly appreciated as the wife is doing breast cancer treatments and we have no way getting there. I know it was deliberately done just don't know what they would have done also no codes present.

[@jmacedo7]

Hi: Dr.Shock, looking for a question, I found the Passlock II module but with another numbering # 16264975. I had said that the difference with ending 55 and 65 is for the type of weight load of the vehicle. Now I ask you as an expert that you are. If one day I don't find the ending 65 and only pure 55, you think they are compatible, you will be able to start the vehicle or if the way you operate changes. For your attention thanks.

[@DrShock]

The 75 and 85 are intended for a G van. Not for a C/K truck. No, they are not interchangeable. To program the module successfully in order to allow for you to start the truck, you need the correct module GM part number matching your factory original powertrain setup.

[@germanhernandez4693]

@drshock chevy astro module is interchangeable whit gmc safari .... both has same part number ..

[@geodure3404]

Thanks for the great video I love it, I have this issue with my 1998 chevy suburban 5.7l crank no start,no fuel to the injectors ,but will start when spray starting fluidity the intake ,also I replaced crank sensor,cam sensor and ignition module sensor,and still no start,please help me here ,I ran out of options.

[@DrShock]

Thanks. This video is about an expected fuel shutoff due to a Passlock security module failure. If you have no fuel to the injectors, then it's not going to start. Rather than throwing more parts at it, you need to debug the problem to root cause first. So I would recommend you start with identifying the cause for the lack of fuel pressure. You'll need a fuel pressure gauge to get anywhere with this sort of problem. There will be port on the 5.7L engine fuel inlet line to connect this type of gauge.

[@niso_farmer7047]

I plugged in the new security module and the security light turned off , I’m stuck now and it still won’t start

[@dawsonblanchard5832]

@@niso_farmer7047 you have to re learn your key after changing the box

[@rh9721]

Thank you for this excellent video. Im having this like problem with my S-10. Ive looked online to finda new module but havent found one. My truck is a 2000 with 2.2L I4 engine. Can you verify that my truck has this module and where I might find one to replace it with? Thank you. I would appreciate any guidance you might give me.

[@DrShock]

These are discontinued parts from GM now. But there is a search link in the description that might turn one up.

[@jsdlandscape]

If my security light stays on the whole time, doesn't flash at any point or go out after 10-15 mins, can the whole passlock system be bypassed to fix my problem? 2000chev 3/4 ton with 454. Thanks

[@DrShock]

I would start with what codes are scanned to guide diagnosis. You may have to pay a shop to do the diagnosis as these kinds of problems can be very difficult to triage without the factory service information, bi-directional scan tool, and other special tools.

[@jsdlandscape]

Thank you for the reply

[@geodure3404]

But I am still getting code 1345 crankshaft sensor

[@niso_farmer7047]

I plugged in the new security module and the security light turned off , im stuck and don’t know what to do , still won’t atart

[@DrShock]

Did you perform the module relearn procedure shown in the video?

[@niso_farmer7047]

@@DrShock ya but no light ever came back on , I have a simple code reader but I can’t check much except codes

[@DrShock]

If it performed the blinking/solid security light dance I showed, then it _learned_ and that's not the problem. If anything deviated from what you saw in the video, then the learn failed. But without a bi-directional scan tool there's not much chance of finding out why. Presuming it did learn successfully, and the security lamp being out indicates that it may have, I would treat this as a multi-failure situation and just begin debugging the secondary issue now that security has been eliminated. Debug getting it to crank, then debug getting it to provide fuel pressure, and then debug getting it to provide spark.

[@scottmcdermott4138]

Wow that’s the best informational video I have found . I’m having a similar problem with a 98 c1500. Mine seems to only have a pass lock start and instantly die ( security light stays on ) when there is additional moisture in the cab. Example I spill a cup of coffee and clean it up but next morning no start , open the windows and wait a few hours .. it’s fine . If I forget and leave my windows open at night it won’t start when I try to leave for work at 5:30 am . I started to see a pattern with moisture when I removed the seats and shampooed the carpet … wouldn’t start for days . Any ideas ?

[@DrShock]

Thanks. Your situation sounds like a wiring harness issue, with the wiring behind the drivers side dash area, behind the center dash area under the radio, or the passlock module itself. Somewhere you've likely got some exposed wiring to a ground, or an exposed circuit board in the module itself, that the moisture is taking advantage of to interrupt the circuitry to prevent communication to the module and cause the security failure.

[@geraldturner8377]

What book is that

[@DrShock]

GM factory shop manual, they are long out of print but there's a link in the description where used ones pop up from time to time.

[@brandonflores5225]

Hey my light isn’t flashing just stays on

[@jsdlandscape]

I'm having same problem. Solid on. Doesn't flash. Also have aftermarket security and heard they could be fighting each other

[@101trayday]

I have no voltage on b8 to b1 any ideas please?

[@IsraelCisneros-uk1gg]

I have the same issue im not sure what it is i been trying to fix this for months

[@IsraelCisneros-uk1gg]

No voltage on b1 to b8

[@DrShock]

Using the schematic view at 7:45 a failure of the first test is pointing to a wiring harness problem. You're going to want to find the wiring harness damage that is either an open preventing the ground circuit to connector pin B1, or an open preventing battery voltage to connector pin B8. No voltage measured between these two is strictly a wiring harness circuit test failure. You can do a continuity tst on B1 to easily tell if the ground is open circuit. But tis will be a tedious and time consuming diagnosis, as you will have to trace the _entire_ run of the wiring harness for the particular circuit involved. Start with a visual inspection first, sometimes you will find the damage that way. Don't forget to inspect connector pins as well for corrosion.

[@pedroandrade4217]

Por favor lo necesito en español

[@danwebb1170]

What do we do when out in Sand dunes 100 miles away and it decides to Fritz out again - do we watch the video over or wish we had BYPASSED this mess, the Cods are not wrong the Whole thing is what is wrong

[@jamesconley6897]

Vyg