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Thread: CEL just came up..

  1. #1
    Tuner in Training
    Join Date
    Jul 2012
    Location
    near Asheville, NC
    Posts
    49

    CEL just came up..

    I was driving yesterday and got my 1st CEL. I ran VCM scanner this evening and got the codes. [ECM] P0121 TP Sensor Circuit Insufficient Activity (Old) (History) (Immature) and [ECM] P0121 TP Sensor Circuit Insufficient Activity. I had installed a VMAX port and polished throttle body about two months ago and all has seemed fine. I am curious as if this is related to it. The only change I made back when I installed the throttle body was Engine>Idle>Airflow>Base Running Airflow>Airflow Final Minimum. I lowered these values by 25% to help idle. Any ideas? and what does this error mean? Possible scenarios that could happen with this error present? How to correct?

  2. #2
    Senior Tuner
    Join Date
    Dec 2009
    Posts
    1,084
    Bad tps, bad connection, harness fault are most common.
    Could be PCM but unlikely.
    Hard to say if its a tune issue without looking at file but I suspect a bad TPS or connection.

    Will need to scan and log tps

  3. #3
    Tuner in Training
    Join Date
    Jul 2012
    Location
    near Asheville, NC
    Posts
    49
    Well, all seems ok for now. All day today, the CEL light has vanished and the errors are gone. I made no change of any kind.