security lights stays on and more

[pottss55]

02 silverado 4x4 with 4.8 auto. Here we go truck won't start or would just start for a second and quit .Finally it starts every since but ! security light stays on even with key out and gas gauge,and temp gauge don't work .gear selection doesn't highlight.air bag light is and abs lights are on. massage center rolls from security ,service 4x4 battery low and low fuel plus scanner won't communicate. what I have done is check battery and alt. for proper power,metered every fuse, tried the 10min. cycles to relearn the passlock.Nothing has change. This all happen at once now i don't even dare to drive out driveway . Just learning about bcm not sure of all its function I have actron cp180 scanner that has endless functions not sure if i can access bcm with it. all info will be helpful and Im not ready to knuckle under to dealer .Thanks

[MT-2500]

Originally Posted by pottss55

02 silverado 4x4 with 4.8 auto. Here we go truck won't start or would just start for a second and quit .Finally it starts every since but ! security light stays on even with key out and gas gauge,and temp gauge don't work .gear selection doesn't highlight.air bag light is and abs lights are on. massage center rolls from security ,service 4x4 battery low and low fuel plus scanner won't communicate. what I have done is check battery and alt. for proper power,metered every fuse, tried the 10min. cycles to relearn the passlock.Nothing has change. This all happen at once now i don't even dare to drive out driveway . Just learning about bcm not sure of all its function I have actron cp180 scanner that has endless functions not sure if i can access bcm with it. all info will be helpful and Im not ready to knuckle under to dealer .Thanks

Check all fuses for 12 volts both sides and all power and ground feed.
Make sure battery voltage is good and battery cables pos and ground good.

[pottss55]

I have metered all fuses got audio on all have 12.6 v @battery and 14.5 @ alt thanks plus cig lighter has power same source of power for ob 2

[j cAT]

Originally Posted by pottss55

I have metered all fuses got audio on all have 12.6 v @battery and 14.5 @ alt thanks plus cig lighter has power same source of power for ob 2

the engine/frame ground points are not good on these vehicles...remove clean re-install ...

the ground on the frame rail under the driverseat area is a known issue..

[pottss55]

great news! i took key switch out and cleaned and now key won't even engage starter . tried the series of 10 minute relearns but nothing .I have also clean all grounding straps i could find and replaced a couple . She looks good in garage

[j cAT]

Originally Posted by pottss55

great news! i took key switch out and cleaned and now key won't even engage starter . tried the series of 10 minute relearns but nothing .I have also clean all grounding straps i could find and replaced a couple . She looks good in garage

you have to relax...when you troubleshoot these weird auto electrical problems you must go one step at a time to narrow down the cause of this..your problem is weird...you must now go back and re do your work to find what you changed to cause this not to attempt to start..


when responding you need to give tech details like voltage checks , and any other observed vehicle behavor...

the other possibility is rodent damage,,,then there is bad fuse sockets...

because the fuses are hard to remove it is found that people rock the fuse so hard the fuse no longer sets into the socket securely then you will loose power to the componet part..

removal of the computer/pcm connectors and check for corroded connections green goo..

post findings it can be repaired ..

[pottss55]

I caved in took truck to dealer , they replaced ignition switch, key cylinder was fine .they cleared all codes and 400 bucks im down the road. I was told that something in switched failed triggering everything so that computer mods were not communicating

[j cAT]

Originally Posted by pottss55

I caved in took truck to dealer , they replaced ignition switch, key cylinder was fine .they cleared all codes and 400 bucks im down the road. I was told that something in switched failed triggering everything so that computer mods were not communicating

thanks for this info..this should help others.

[pottss55]

j cat thanks for all your info i used it all , i found things that i wasn't looking for or never new to look for . I have read these forums alot and can usually get get to bottom of issues .I have an actron scanner that I'm still learn all of it capabilities . I'm always surprised to see that my problems are not unique but mostly common . thanks again Bryan

[pottss55]

My trouble are not over . Driving today and message center starts rolling threw all messages gas and temp quit, shift lite quit and air bag lite is on .Truck runs fine but have no faith in driving it.Plug in scanner every thing goes back to normal, unplug scanner and everything goes hair wire. scanner is reading computer Truck does run not sure if relearning passlock will help and had to disconnect battery because security light stays on all the time

[pottss55]

final verdict : pcm ground was corroded ,pcm was full of water and wires was all corroded at plug . cleaned and dried everything and packed with grease been a week and no issues yet!

[j cAT]

Originally Posted by pottss55

final verdict : pcm ground was corroded ,pcm was full of water and wires was all corroded at plug . cleaned and dried everything and packed with grease been a week and no issues yet!

that is something that is a problem in the rust belt..the corrosion of the componets in the wheel well area need greater protection..the wheel well on my vehicle I added a rubber roofing material that extends down a few inches this keeps the road chemicals away from the engine compartment...also in the winter I cover the lower half of the radiator with a plastic shield this also helps ..

you will need to inspect all your electrical connections every year and use the silicone dielectric grease...I hope that the PCM was cleaned well using denatured alcohol is safe. using some heat like 100deg f to dry out works good..