2002 yukon won’t start
Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=102234
Printed Date: May 16, 2025 at 7:29 PM
Topic: 2002 yukon won’t start
Posted By: turtlesplatter
Subject: 2002 yukon won’t start
Date Posted: February 15, 2008 at 5:21 PM
Hey all! I am by no means an installer but I am a pretty good DIYR. I'm having a major problem with my brother's Viper 771xv. Basically, his 2002 Yukon will not start. When I turn the key the dash comes to life but will not start. At first we tried jumping it but that didn't do the trick (didn't think it would becuase there is power in the vehicle). I'm thinking it's the alarm because even though I am able to disarm the alarm, it seems to be behaving as if the engine kill has been activated. I want to take it back to the installer (Best Buy) to get them to look at it but can't since the vehicle won't start. Any suggestions on what to check or how to bypass the alarm or simply how to disconnect it so we can at least get it started or something? Thanks!
Replies:
Posted By: Big Dog
Date Posted: February 15, 2008 at 6:15 PM
First of all, does it remote start? If not, what does it do? Remote start bypasses the built in starter kill. The built in starter kill disarms with the alarm but might be set to kill the starter 30 seconds after disarming so you need to try key starting within 30 seconds of disarming. Press the disarm button twice the immediately try to key start. If you find the 771 "brain" follow the rainbow colored cable which will lead you to the external relay pack. On the external relay pack the starter wire from the ignition switch enters on a heavy gauge green and exists via a heavy gauge purple. Use a test light to see if there is current on the purple while you crank the engine. If you do then it's not the 771's fault. The Yukon's starter wire at the ignition switch is yellow. ------------- Prepare your future. It wasn't the lack of stones that killed the stone age.
Posted By: turtlesplatter
Date Posted: February 15, 2008 at 7:21 PM
Big Dog wrote:
First of all, does it remote start? If not, what does it do? Remote start bypasses the built in starter kill. The built in starter kill disarms with the alarm but might be set to kill the starter 30 seconds after disarming so you need to try key starting within 30 seconds of disarming. Press the disarm button twice the immediately try to key start. If you find the 771 "brain" follow the rainbow colored cable which will lead you to the external relay pack. On the external relay pack the starter wire from the ignition switch enters on a heavy gauge green and exists via a heavy gauge purple. Use a test light to see if there is current on the purple while you crank the engine. If you do then it's not the 771's fault. The Yukon's starter wire at the ignition switch is yellow.
Thanks for the quick reply (I wish my motorcycle forums were this fast!!) To answer your question, no it will not remote start. All that happens is the lights flash but no go. I actually just got back from Best Buy to talk to one of the installers as to what it could be and he pretty much said the EXACT same thing you said. Said that there "could be" corrosion in the relay pack and once I follow the ribbon cable to the relay pack to give it a tap and see if that will dislodge it. Gonna try that tomorrow as well as your suggestion with the test light (too dark and too damn cold out right now!) Luckily the last installer stuffed the brain right in the fuse box, so that's easy to get to. If the test light does not come on, does that mean that there is an issue with the brain or relay pack itself? Thanks for all your help!
Posted By: Chris Luongo
Date Posted: February 16, 2008 at 8:38 AM
turtlesplatter,
I know this sounds silly, but of course the first step you want to do is make sure all is well with your test light.......ground one end, touch the other end to a known good positive (could be one of the fuses in the car's fusebox), just to make sure the light is good.
And then, basically:
The Yukon's yellow starter wire comes out of the ignition switch, and goes under the hood to the starter motor solenoid.
The installer would cut that yellow wire in half, and connect each half to the Viper's relay pack (thos green and purple wires.)
The Viper's job is to allow that yellow wire to simply pass through most of the time, but "break" it when the alarm is armed, so people can't steal the car.
So basically, whenever we installers cut a starter wire in half like that, we often refer to the two halves we cut as the "key side" and "engine side" or "body side" or "starter side" or whatever you like.......hopefully that makes sense.
--If the "key side" tests good when you turn the key to crank, but the "starter side" tests bad, the Viper's starter kill feature is engaged by the alarm (or is not engaged, and the relay pack is bad).
--If the "key side" and "starter side" both test good, the starter kill is ok, and the problem is elsewhere.
--If even the "key side" tests bad, there's a problem with the car. It could be a defective ignition switch (happens with GM), or other things.
--While you're in there, you'll see a group of thick wires the installer connected to........... two reds, a pink, a white, and an orange.
--The two reds should have power all the time, the pink and white should have power in Run and Start, and the orange (for the heater) should have power in Run only.
--If either of the reds have no power, check the underhood fuses.
--If the two reds both have power, but any of the pink, white, orange or yellow don't function properly, the ignition switch is likely bad.
ALSO:
This vehicle has GM's Passlock II theft-deterrent system. Turn the ignition on, and observe all the lights in the dash. There's one that says "SECURITY."
If it comes on steady for a few seconds, then goes out, all is well. On the other hand, if it's flashing, Passlock has a problem. It may (or may not) be related to the remote starter install.
Posted By: Big Dog
Date Posted: February 18, 2008 at 7:34 AM
Because it doesn't remote start nor key start it might be the OEM starter relay or the neutral safety switch or even worse - the starter. But let's not jump to that conclusion yet. If it cranks with the key but doesn't start then it might be Passlock related - but if I understood correctly it doesn't even crank so it can't be Passlock. Let's start with testing the heavy purple of the relay pack. If there is power at the purple then crawl under the truck and see if the crank signal comes to the starter. Let's hope it's not the starter. ------------- Prepare your future. It wasn't the lack of stones that killed the stone age.
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