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Thread: 2008 Tacoma - Knock Sensor Limp Mode

  1. #1
    Tuner in Training
    Join Date
    May 2015
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    26

    2008 Tacoma - Knock Sensor Limp Mode

    We just had a customer bring in an 08 Tacoma with an Automatic Transmission.

    The vehicle is not in for a tune, but a complaint of a P0333 Knock Sensor #2 error. The Knock Sensor location is time consuming to get to and we we're asked to disable the code. When the P0333 sets on this Vehicle, Overdrive is also disabled in the Transmission as some kind of LIMP mode.

    We have now paid for credits, unchecked the Knock Sensor #2 codes and now no codes are reported via a DTC scan. The Vehicle however remains unable to shift into Overdrive. Its looking like that the Toyota Support for DTC's is simply a turn the light off, rather than disabling code and whatever limp/error modes that may be accompanied by it.

    I hope that this is something that can be looked at by the Toyota Developers as we are currently no further ahead than just removing the Check Engine bulb.

    Ticket has been opened but I've been told that Tuning issues are no covered under support - I believe this to be a software issue rather than a "tuning issue".

    Ticket Details
    Ticket ID: 175288
    Department: Support (Existing Customers)

    Daniel @ Post-Haste Performance

  2. #2
    Tuner in Training
    Join Date
    Mar 2019
    Posts
    31
    Hello Daniel,

    Unfortunately I can't help you with the limp-mode aspect of the DTC you're getting. Disabling specific DTC's on the Tacoma does in fact seem to only turn off the CEL for a given code.

    But bringing this back around to your specific issue.. It's been a pretty common occurrence to have rodents chew these wires in Tacomas. Many threads over the years have made their way onto various forums. Perhaps you can locate damaged wiring and repair easier than R&R the sensor itself which might be just fine anyway.

    Check out this thread for an example:
    https://www.tacomaworld.com/threads/p0333.478747/

  3. #3
    Tuner in Training
    Join Date
    Mar 2019
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    10
    I've seen the same issue on a Highlander with the 3.0-liter V6 - knock sensor circuit fault causing no overdrive. Indeed the knock sensors are not so easy to get to and require removal of a lot of stuff out of the way. The repair was done by replacing the knock sensor harness extension and both knock sensors. While we were at it we replaced the coolant hoses through the valley. By the way, suppressing DTC's from the binary can sometimes have unpredictable effects on runnability. For example it's known that for one Toyota vehicle suppressing a throttle body DTC leads to a no-start. While the DTC codes themselves are very easy to locate and edit in the binary, the underlying logic is not so.