Have a 99 silverado with code 1626 what can I do

copy and paste

https://haynes.com/en-us/tips-tutorials/2007-13-chevy-silveradogmc-sierra-truck-routine-maintenance-faq


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P0137 is an O2 sensor low voltage code. bank 1 sensor 2. This could cause a rough start. The sensor that needs replaced is on the drivers side, after the catalytic converter

Code U1000 is saying the ECM lost communication with the BCM which can happen when the key switch is turned far enough to stop the engine but not enough to turn the accessories off.
Code 463 is for fuel level sensor circuit high which is a problem with the fuel gauge or the sending unit in the tank.
Code 1626 involves the theft deterrent system.
P1626 CHEVROLET - Theft Deterrent Fuel Enable Signal Not Received
Read more: http://engine-codes.com/p1626_chevrolet.html#ixzz210PRFRO9

The code 1626 could be the issue - the passkey system may not be reading the chip in your key.

That's will explain they security light problem http://vatspasslockpasskeysecurityhelp.yolasite.com/

what kinda code does it have in it. need to know the code before we can help

p0300 is a random misfire. A scanner will need to tell the primary cyls that have problems. A (qualified) repair shop will need to check it. Could be from vac leaks, to fuel pressure, to spark problems????/

codes p0420 and p0430 are both post o2 sensors, the ones after the convertor, both sides if replacing

is it that the plug on each is different? or are the wires color coded different on each?

I had the same exact problem at 175000 miles on my '99 Silverado..after paying the garage several times to read the computer codes to me and ex-plain that 1st I needed an $899.00 head gasket repair, and then just a $250 injector replacement, I decided to run some injector cleaner throguh the system...guess what?............I cetainly am glad I didn't have the head gaskt repaired or the injector replaced...problem fixed

COULD BE CONTROL MODULE OR WIRING PROBLEM,BAD GROUND.RUN CODES IT SHOULD TELL YOU SINCE EVERY TIME YOU START IT RUNS DIAGNOSTICS