Factory Alarm Disable, 2000 Tahoe

hey guys my factory immobilizer (fuel cutoff) is causing intermitten problems with the starting of my 2000 z71 old body style tahoe 5.7l. Do any of you know how to disable the factory immobilizer. any help would be much appreciated. this is a thorn in my side.

The Tahoe has used a Passlock2 since 1998. Your gonna need a bypass module like the 555L....

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Mike M2
Tech Manager
CS Dealer Services

oh ya i know that, i have had the alarm in for over a yera now (viper 791, remote start window modules, backup battery) so ya i have already used the 555l, But my problem is with the factory disabler itself, The problem is happening when i start with the key, so that rules out a problem with the 555l(i unplugged it just to make sure though). when i go and crank the car starts but immediatly dies. So that leads me to beleive it is the factory system acting up.

hi! there is a way   to cancel  the immobiliser   system     you will need to cut  the  yellow  wire  from the key cylinder   and   to find out the resistor value

there is tree wires going to the key cylinder  one white 

                                                                           one black or ORANGE / black     

                                                                           one yellow

you will need a ohmmeter to mesure the resistance between the blk and yel  from the key side   black lead from the meter to blk wire  and red lead to yel from key side that will give you a value when key is turn on ( ex. 4.3k ) turn key off  and reverse the lead from the meter  the red lead to the blk wire and the black lead to the yel from the key side      turn key on and check the value again  (ex.2.65k )  now add the two value and divide by two  this will give you the value of the resistance of the passlock system    Now  you need to attach  this resistor  value  between the black (ORANGE / blk) and the yellow wire of the passlock  but leave the wire cut  and attach to the one opposite to the key cylinder.    good luck

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cocolaboy

When it dies does the security light start flashing?

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Mike M2
Tech Manager
CS Dealer Services

Bluehoe, the oem security is only a content theft system meaning that it only honks the horn and flashed the lights, but doesn't do anything with the ignition system. The problem your having is with the Passlock II system and the resistor value from the 555L. YOu may have to reprogram the system or replace it. I've had some systems do this to me where it would work fine for the first little while and then the customer would call me back saying that they can't start the vehicle with the key and sometimes can't start with the RS either and I replace the module and all is good.

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Jeff
Velocity Custom Home Theater
Mobile Audio/Video Specialist
Morden, Manitoba CANADA

the thing that makes me think it isnt not the 555l is that when i unplug the 555l, the car will still have the same problem.( i left in unplugged for 2 days and was still having the problem).  And evrythime i remote start the car the car will start with no problems.

If you unplug the 555L it shouldn't start. The resistance wire from your Passlock is running threw it and unplugging it breaks the circuit. I agree with Jeff, the 555L has an issue...

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Mike M2
Tech Manager
CS Dealer Services

what if i just want to disable the factory immobilzer? will what jacqueslacombe instructed me to do work? or is there another way? thanks guys for all the help.