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  1. #1

    Default Help with P0146 OBD2 code, please!

    I hate to be one of the thousands of posters asking for help on chasing codes and illuminations of SES light, but I've reached a dead end and the dreaded light is still on.

    I have a 1997 Silverado K1500 4x4 with 125,000 miles. Original 5.0L 305 and auto transmission. Original cat and exhaust. When I bought it, the light was on (or would've been if the previous owner didn't take the bulb out) and the single OBD2 code is P0146.

    I realize thats Bank 1 sensor 3 no communication. I changed all four O2 sensor's with new Borg Warner ones. Same code afterward. I visually inspected the wires leading with the post-cat sensor and all appears to be untouched OEM work.

    Thorough internet searching isn't leading anywhere so I'm hopeing someone here might have some insight and troubleshooting advice. Any help would be greatly appreciated.


  2. #2
    Master Mechanic zubbiez's Avatar
    Join Date
    Feb 2009
    Eagle Mountain Utah


    I have had that code before tried everything and finally had to change the cat. after that no more code. i also had the same thing happen as far as there where no SAS lights flashing until I had driven the truck a few hundred miles, the guy just reset the code and sold it as is Bastard!
    2000 Silverado Z71 Whipple Supercharger, JBA Headers,3" cat back Flowmaster Exhaust, Volant cai, Pioneer Preimer deck,Orion subwoofer,03 signal light mirrors,03 taililghts

  3. #3


    Are you sure this is a valid code? Does your right bank have 3 sensors?

    2004 SILVERADO 2500HD LS
    Pro Comp Leveling Kit
    285-75-16 Cooper ST All Terrains
    Pro Comp Programmer
    Bilstein Shocks
    Linux Bed Liner
    Tinted Windows

    Other rides:

    1967 Landcruiser <350 Chevy>
    1970 Camaro
    1990 Geo Metro Convertible
    2007 FJ Cruiser

  4. #4


    Thanks for the advise and help in advance.

    There's one sensor on each downpipe from each of banks. There's another sensor just after the "Y" and finally another sensor after the cat, for a total of 4 sensors.

  5. #5


    OK, the next step is to see if the sensor is working. That's easy with a scanner. A scanner will show the feedback. If the sensor is working and there is no activity then your cat is probably bad. If the sensor were bad it would set a heater code or a voltage code.

  6. #6


    I'm tempted to believe the sensor is working, as this same code (P0146) arrived with both the old sensor and the new sensor. The odds of both sensor's being bad I would imagine are slim. Would you agree?

    Last night I inspected the connector and all 4 prongs appear to be in working order. I backprobed the connector on the truck side with an analog voltmeter and confirmed all wires were seated.

    What type scanner are you referring to? I have a OBD2 code reader but I'm guessing that's not what your referring to.

    Thanks a ton for your help thus far. I really appreciate it.

  7. #7


    You need a scan tool that can read data like a SnapOn, Genysis, Tech II. You are correct in that the sensor is probably working. If you research this code on Google and other forums you will see that most of the time the cat is the problem but I would verify sensor feedback with a scanner first.

  8. #8


    you dont need any tools at all change your cat. This should fix the problem I had the same code after removing my cat.
    08 silverado
    K&N cai
    single in dual out cherry bomb pro
    leveling kit
    custom painted bow ties
    Bed liner
    Tinted windows
    20inch Cruser Alloy Switchblades
    Goodyear Eagle GT2 285/50/20
    1 truly heavy foot + Wait4meperformance SCT Handheld
    100 shot of Nitrous Dyno tune system
    SS front bumper
    Matching painted front grill and bow ties

  9. #9


    Thanks to everyone for your input and advise. After I change the "Y" pipe and cat I'll be sure to update this thread.

    Thanks again.

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