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OBD2 problem

Discussion in 'General Chevy & GM Tech Questions' started by hayking, Apr 26, 2008.

  1. hayking

    hayking New Member

    Hi, have a 01 chev suburban. Check eng. light came on. Went to 2 different places and both could not get codes. Scanners should turn on with ign. and they will not. Screen stays blank. There is power to the OBD2 16 pin outlet port under dash, I believe on the bottom right. Also tried a friends new code reader which works perfect on my other truck but will not turn on with suburban. Any ideas? Thanks
  2. MrShorty

    MrShorty Moderator Staff Member 1000 Posts

    My first thought was to check the OBD-2 connector power supply, but you indicate that it has power, so I will assume that it has power (though if you need to double check that, be sure it has power. It seems that most cases like this are the result of no power to the connector like when the fuse blows (I think it's the cigarette ligther fuse that feeds power to the OBD2 connector)).

    Are the connector grounds good?
  3. hayking

    hayking New Member

    I beleive the grounds are OK. Just to be sure I jumped a 22ga. solid wire from gnd. pin to chassis grd. Still nothing. I also checked continuity from both grds to chassis grd and seemed fine. I believe there are 2 grounds on connector, chassis and signal. Less than 1 ohm on both. I get power (12vdc) from pin #16 with ign. on or off. If I check from pin 16 to pin 4 or 5 I also get 12vdc. THIS IS DRIVING ME NUTS !!! Could it be a problem with the PCM? HELP!
  4. MrShorty

    MrShorty Moderator Staff Member 1000 Posts

    I'm sure it could be a problem with the PCM. Diagnosis is about sorting through the possible causes to find the real cause. Unfortunately I have no experience diagnosing this problem beyond checki9ng for power to the data link connector. If you can find a good wiring diagram, it might be worth the effort to make sure all the connections/wiring between the OBD-2 connector and the PCM are intact.
  5. hayking

    hayking New Member

    WHEW....3 1/2 hrs later and it was a bad connection under the dash. Repaired that and scanner worked wonderfully. Now I have a P0440 code to troubleshoot. I tell ya the fun never ends! Thanks for the advice, I really appreciate it.

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