Results 1 to 4 of 4

Thread: LS376 E67 fan won't shut off. HELP!!!

  1. #1
    Tuner in Training Acerni's Avatar
    Join Date
    May 2013

    LS376 E67 fan won't shut off. HELP!!!


    I have this tune from GM LS3 E67. Fan will start but won?t shut off. I've read that it need that the vehicle reach up 40mph to have the fan system works properly but my VSS isn?t connected because old vehicle.

    Read also another post about the van delay and tried to modify it but no luck.

    I?m installing a SPAL PWM fan and tried also the PWM Electric @125Hz but seems not working for my fan.

    Any suggestions will be apreciated.
    Attached Files Attached Files

  2. #2
    Advanced Tuner
    Join Date
    May 2006
    Seattle, WA
    Redo your 18040 table, Fan State transition. You 0->1 means turning on, 1->0 means off. Both are set to 100% DC, so even if the ECM commands it off via ECT or AC pressure, your calibration is telling it to stay on. In this state, it will only ever turn on at 100%, there is no middle ground or off state. I don't know what values work for the GMPP calibration, start with like 50 in the 0->1 and 1->0 and see if that works.
    2013 Sonic RS - manual, CGM, 6M, sunroof, mods in process
    2008 TrailBlazer 3SS AWD LS2, loaded, dropped, modded, SE22 Performance tuned. And then some...
    2002 TrailBlazer LT 4WD 4.2L I6, lifted, tires, exhaust, SE22 Performance tuned

  3. #3
    Advanced Tuner
    Join Date
    Oct 2013
    Common complaint with the later GMPP controllers. See the thread linked below.

    Despite this conversion being in an older vehicle, a VSS signal to the ECM will improve driveability and allow the fan to turn off, once the vehicle is in motion.

    You could flash an older GMPP calibration with the same operating system (12638778) into to your ECM to gain fan control when stationary - but this option is no free lunch either - you would then have to retune for your specific airflow model.

    I believe the SPAL PWM fan controller uses the reverse logic of the GM ECM output. I recall there being a thread on this forum about this topic.

  4. #4
    Advanced Tuner
    Join Date
    Apr 2017
    Meridian MS
    The logic difference is between SPAL OEM fans & SPAL aftermarket fans. A non-GMPP ECM that has the ability to do PWM fan output will control the OEM fans just fine.