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GMWrencher
GMWrencher, ASE Certified Technician
Category: Chevy
Satisfied Customers: 439
Experience:  100% GM Certified ASE Master Automobile Medium/Heavy Truck. Licensed State Auto Inspector
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99 chevy: no start and security light stays on all time even with key

Resolved Question:

have a code of p1626 on 99 chevy pick up no start and security light stays on all time even with key off and pulled out. any ideas??
Submitted: 6 years ago.
Category: Chevy
Expert:  GMWrencher replied 6 years ago.

Hello, I will do my best to help answer your General Motors Vehicle questions.

 

Just to be correct is this the new body style Silverado?

 

 

Customer: replied 6 years ago.
yes ls model
Expert:  GMWrencher replied 6 years ago.
Have any repairs been attempted?
Customer: replied 6 years ago.
nothing yet
Expert:  GMWrencher replied 6 years ago.

Ok for some reason your vehicles engine computer is not receiving the security data from the body computer.

 

 

Will it spin over?



Edited by GMWrencher on 8/9/2010 at 9:25 PM EST
Customer: replied 6 years ago.
yes cranks over fires then dies
Expert:  GMWrencher replied 6 years ago.
Have you had the all the modules scanned for codes or just the PCM (engine/trans)?
Customer: replied 6 years ago.
just engine for some reason my snap on scanner wont communicate with bcm. where is bcm located??
Expert:  GMWrencher replied 6 years ago.

Under the steering column, its a programmable module, cant just swap it out.

 

Try to relearn the pass lock first.

 

Procedure as follows

 

Time required, approximately 30 minutes.

Ensure that the battery is fully charged, ad a second battery or trickle charger as required.
Use the scan tool to clear the DTCs or disconnect the battery negative cable for 1 minute.
1 Turn the ignition switch from the OFF position to the CRANK position allowing the vehicle to try and start. The vehicle will start and then stall.
2 Leave the ignition switch in the ON position while observing the security indicator with the doors closed.
3 When the security indicator turns off, which can take up to 10 minutes, turn the ignition switch off. Wait 10 seconds.
Repeat Steps 1-3 2 more times (3 times total).
The BCM and the PCM/VCM will learn the new code on the next start attempt.

Expert:  GMWrencher replied 6 years ago.
Be sure on the last 10 minute learn to cycle the key off BEFORE trying to start the truck.
Customer: replied 6 years ago.
tried that my security light never turns off just keeps flashing fron that to battery light
Expert:  GMWrencher replied 6 years ago.

You posted you had not tried any repair attempts... You most likely have a bad passlock sensor or column wiring harness.

 

The passlock sensor is part of the ignition lock cylinder case. It requires the a special lock plate press to access it.

 

Condition(s) may be due to an incorrect Passlock sensor voltage received by the body control module (BCM) from the Passlock sensor due to the following conditions.

A 7 ohm variation in the sensor ground circuit wiring, circuit 1057

A 100 ohm variation in the Passlock sensor signal wiring circuit, circuit 1836

 



Edited by GMWrencher on 8/9/2010 at 9:55 PM EST
GMWrencher and 3 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
why is my secuirty light on even with the key off and out??
Expert:  GMWrencher replied 6 years ago.

It will be on until you close the door. It should flash as soon as you open the door and stop flashing when you close the door. Is that correct? If not please explain what the symptoms are.

 

One more thing, to save some money you may want to buy the bypass kit for the pass lock sensor. It is much cheaper and more reliable. Its up to you to research and choose a brand.



Edited by GMWrencher on 8/10/2010 at 12:43 AM EST
Customer: replied 6 years ago.
door is closed security light stays on all the time will run down battery. what brand of aftermarket bypass you talking??
Expert:  GMWrencher replied 6 years ago.

Is your light on or flashing? If it stays on/flashing thats a problem with content theft security also.

 

Companies that sell remote start systems have a bypass kit to eliminate the pass lock sensor.

 

That is something I did forget to ask you. Do you have any type of alarm or remote start? If so it changes the entire diagnosis.

Customer: replied 6 years ago.
no alarm no remote. just starts up and dies turn key off pull key light stays on constant will run down battery
Expert:  GMWrencher replied 6 years ago.

Your vehicle has 2 separate functions as a theft deterrent.

Content theft, sounds horn if an attempt to break in while locked.

Theft deterrent, kills fuel injectors after attempt to start.

 

Since you have a current code Id start with that, but you may have to access the BCM functions and data to diagnose the remaining.

 

Depending on how much time and money you want to spend, you can either replace the pass lock sensor and column harness, or bypass the sensor with a kit or a resistor, if your electrical savy. The bypass is cheaper and reliable.

 

Just search how to bypass GM Pass lock.

 

I dont endorse a particular brand, because I make my own with resistors from radio shack.

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