Code P0056 - '01 LW300

Discussion in 'Saturn L-series' started by Oppie, Mar 9, 2007.

  1. Oppie

    Oppie Guest

    SES light came on the other day and I did the usual first try of pulling the
    fuse to reset the controller. I had gotten gas the night before and it was
    plausible that this was a problem. No good, Engine started and light stayed
    off but came on again at next engine start.

    Borrowed a Snap-On scanner from a friendly garage and found the following
    codes set:
    P0056 HO2 heater circuit bank2 sensor2
    P0161 O2 heater circuit bank2 sensor2
    P0160 low O2 activity bank2 sensor2
    P0159 O2 sensor slow bank2 sensor2

    Following resetting the codes, the P0056 came up again immediately so, guess
    that is the primary problem. Will pick up a new sensor tomorrow. Engine has
    98K on it so can't complain that it needs a new sensor.

    Scanner shows that both upstream O2 sensors (sensor1) are running in closed
    loop and are normal. Both downstream sensors show open loop but that is
    normal as I understand it.

    The problem sensor is the bank2 (against firewall) downstream. If there is
    no compelling reason to replace both sensors, just going to replace the one
    (but with a Bosch sensor).
     
    Oppie, Mar 9, 2007
    #1
  2. Oppie

    Oppie Guest

    My buddy at the garage identified bank 2 improperly as being against the
    firewall. Bank 2 is front (against radiator). Checked this from the service
    manual.
    Pulled the connector and tested heater circuit with ohm meter and it was
    indeed open. Getting the connector apart was the hardest part. First the
    latch holding the connectors to the bracket is gently squeezed with a pliers
    to release it. The red latch mechanism was pretty stuck and I had to beak
    off a few black tabs in order to get it to move. The red latch gets pried
    out to the side to release the O2 sensor connector. To re-attach it, gently
    mate the connectors and push in the red latch slide to lock in place.

    Bosch universal sensor cost about $100 and came with the necessary splices
    to use the original connector. Codes reset and all good now.

    Since the harness was run in such tight quarters, before pulling out the
    original sensor harness, Tie a string to the connector and as the harness is
    pulled out, it pulls the string through and makes it easy to pull the new
    harness into position.

    Oppie
     
    Oppie, Mar 11, 2007
    #2
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