Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

OBD II code help

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by lugnut, Aug 30, 2005.

  1. lugnut

    lugnut 1/2 ton status

    Joined:
    Aug 3, 2001
    Posts:
    268
    Likes Received:
    0
    Location:
    North Carolina
    Anyone know where I can find somthing explaining what might cause a code? I have a P0420 on a 2000 Sunfire with a 2.2L and I need to know what the cause might be. O2 sensor , cat , O2 sensor after cat somthing else ? Mods sorry this is not a truck but it is tech and the info could also be used on a truck. Thanks Allen
     
  2. readymix

    readymix 3/4 ton status

    Joined:
    May 30, 2004
    Posts:
    6,706
    Likes Received:
    26
    Location:
    Murrieta, California
    I will look it up in the TEC2 book and post up all the info i can find
     
  3. readymix

    readymix 3/4 ton status

    Joined:
    May 30, 2004
    Posts:
    6,706
    Likes Received:
    26
    Location:
    Murrieta, California
    Sensed Parameter
    - Catalyst Monitor AMT

    Faulty Code
    - P0420

    Monitor Description
    - Detects a catalytic converter with unacceptable amounts of oxygen storage capabilities

    Critera and Thresholds
    - Oxygen Storage Capability (OSC) Time Difference > 0.182 sec
    OSC Time Difference = OSC Worst Pass
    Thresh - OSC Compensation Factor * (O2S 2 Response Time - O2S 1 Response Time)
    OSC Worst Pass Thresh = 1.820 sec

    Secondary Parameters and Enabeling Conditions
    - Engine speed > 1000 RPM for minimum of 34 sec since end of last idle period
    Predicted catalyst temp > 345C, < 450C
    Baro > 72.3 kPa
    IAT between -20.5C & 80C
    ECT between 70C & 125C
    Idle < 45 sec
    MPH < 3
    Test attempted this trip < 12
    -75 RPM < (Engine Speed - Desired Speed) < 150 RPM
    Engine run time > 520 sec
    Battery voltage > 9 V
    Flow < 7 g/sec
    Rapid Step Response Enable Criteria
    OSC Time Difference Step > .590 sec
    OSC Time Difference Step > 0.00 sec
    None of the following DTC’s set:
    105, 107, 108, 112, 113, 117, 118, 122, 123, 131, 132,
    133, 134, 1133, 137, 138, 140, 141, 171, 172, 200, 300,
    325, 336, 340, 341, 440, 1441, 442, 446, 452, 453, 480,
    481, 502, 503, 506, 507, 601, 602, 1621

    There is also a sedondary test ran which can also set this code. From what i am reading it just varies the thresholds and conditions too check the system again.
     
  4. lugnut

    lugnut 1/2 ton status

    Joined:
    Aug 3, 2001
    Posts:
    268
    Likes Received:
    0
    Location:
    North Carolina
    :doah: My head hurts now. So are you saying the computer is comparung the readings from the O2 sensor before the cat to the O2 sensor after the cat ? I had the cat replaced about 5,000 or 6,000 ago.
     
  5. readymix

    readymix 3/4 ton status

    Joined:
    May 30, 2004
    Posts:
    6,706
    Likes Received:
    26
    Location:
    Murrieta, California
    But did you replace the O2's?
     
  6. lugnut

    lugnut 1/2 ton status

    Joined:
    Aug 3, 2001
    Posts:
    268
    Likes Received:
    0
    Location:
    North Carolina
    No. I was trying to save some cash.
     

Share This Page