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ThunderMax ECM with AutoTune Closed Loop System
Made in U.S.A.
42 Reviews

ThunderMax ECM with AutoTune Closed Loop System


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J&P Part #:  834-338
Mfr Part #:  309-588

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ThunderMax ECM with AutoTune Closed Loop System
ThunderMax ECM with AutoTune Closed Loop System

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ThunderMax ECM with AutoTune Closed Loop System

ThunderMax ECM with AutoTune Closed Loop System

Order in the next to ship today

Product Details


Description for ThunderMax ECM with AutoTune Closed Loop System

• ThunderMax ECM with AutoTune module mounts conveniently in place of the factory ECM and plugs in to the existing harness

• Maps, software and firmware updates available on line at no charge

• Quickly find the best map for your application using SmartLink Map Filters

• With the AutoTune, AFR tuning for component and exhaust changes are self-adjusting-simply install, download a map and ride while Auto-Tune maintains target AFR in all conditions

• Includes ThunderMax ECM and AutoTune Module, plug-in harness and two wide band sensors, SmartLink Software and communication cable, Quick-Start Easy Install and Comprehensive User's Manual, technical support and free software and updates

• Select and install a matching base map and enjoy the efficiency of a balanced fuel curve for throttle response like you have never imagined

• No extensive dyno tuning required for most models

• Alpha-N design unaffected by long duration camshafts

• Replaces factory ECM - easy plug-in installation and set-up

• Simple adjustable rev limit, idle, speedo calibration and decel pop control settings

• Easily adjust fuel, ignition timing and cold start maps

• Versatile - plug and ride or live-tune a custom application

• Logs engine starts, engine temperatures and total hours of operation time in 100 RPM increments

• Read diagnostic codes through software or traditional methods

• Record live data during riding or tuning sessions; choose replay speed for data analysis

• ThunderMax includes SmartLink Software and cable for easy PC tuning, maps for popular engine combinations and Quick-Start Easy Install and Comprehensive User’s Manual

•This EDM comes with 18mm sensors and the stock pipes have 12mm sensors

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ThunderMax ECM with AutoTune Closed Loop System

Product Specs for ThunderMax ECM with AutoTune Closed Loop System

Manufacturer Part Number:
Open or Closed Loop:
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Fitment Note:

Not compatible at this time with models that have RDRS. Will require the use of an exhaust system with 18mm sensor bungs or head pipes must be modified to accept 18mm sensors.

Fitment Questions?

With over 750 years of experience combined, our tech staff has the answers!

  • Harley-Davidson®

    • Touring Electra Glide Police FLHTP : 2017–2019
    • Touring Electra Glide Standard FLHT : 2019–2020
    • Touring Electra Glide Ultra Classic FLHTCU : 2017–2019
    • Touring Road Glide CVO FLTRXSE : 2018–2019
    • Touring Road Glide FLTRX : 2017–2020
    • Touring Road Glide Limited FLTRK : 2020
    • Touring Road Glide Special FLTRXS : 2017–2020
    • Touring Road Glide Ultra FLTRU : 2017–2019
    • Touring Road King FLHR : 2017–2020
    • Touring Road King Police FLHP : 2017–2019
    • Touring Road King Special FLHRXS : 2017–2020
    • Touring Street Glide Anniversary FLHX : 2018
    • Touring Street Glide CVO FLHXSE : 2017–2019
    • Touring Street Glide FLHX : 2017–2020
    • Touring Street Glide Special Anniversary FLHXS : 2018
    • Touring Street Glide Special FLHXS : 2017–2020
    • Touring Ultra Limited Anniversary FLHTK : 2018
    • Touring Ultra Limited CVO Anniversary FLHTKSE : 2018
    • Touring Ultra Limited CVO FLHTKSE : 2017–2019
    • Touring Ultra Limited FLHTK : 2017–2020
    • Touring Ultra Limited Low FLHTKL : 2017–2019
    • Trike Freewheeler FLRT : 2017–2019
    • Trike Tri Glide Ultra Classic Anniversary FLHTCUTG : 2018
    • Trike Tri Glide Ultra Classic FLHTCUTG : 2017–2019
Product Notes

Important Product Notes

This item cannot be returned once the package is opened. Manufacturing defects must be addressed through the manufacturer directly.

Shipping Note

Due to state regulations we cannot ship this item to the state of California.

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Ratings & Reviews

Help Customers Understand This Product

42 Reviews
Rating Breakdown
5 stars
4 stars
3 stars
2 stars
1 star
July 14, 2021
He loves it. Bike is running great and easy setup
June 28, 2021
Amazing product! Bike runs so much better.
May 10, 2021
Awesome product! I was a little apprehensive picking the right map to load as I have many modifications on my engine. Once loaded it’s been running great and I’m still putting some miles on it to see how the tune goes.
March 18, 2021
well not so good on this item I got to send it back to manufacture cause it won't take a basemap and start the bike and pretty pricey to have that issue out of box new
February 2, 2021
Love ThunderMax autotuners!! I've used them in the past with great results. Yes the up front expense is a bit steep, but it gives you the freedom to change what ever you want on your bike without the hassle of bringing into a shop to get dynotuned every time you change your muffler or head pipe or cams or whatever. I will always run these on my EFI bikes.
January 26, 2021
Excellent service. Willing to price match. Saved money buying from JP cycles
December 1, 2020
The Thundermax ECM with autotune is the perfect fit for my 2019 HD SGS build. The ECM is easy to install, the software is intuitive. My build included a RS468 cam, S&S oil pump, cam plate, tappet cuffs and quickie pushrods and Fueling tappets. I also installed a TAB performance header and B.A.M. Sticks with 2.5 inch baffles. My M8 114 cu. in engine really wakes up between 2,000 and 5,000 rpms.
September 3, 2020
I can't tell you how much JP cycles worked with me on getting the ThunderMax ECI unit installed they helped me and walk me through the programming of the unit their technical support staff goes above and beyond they even called me back to make sure everything was okay. There's only two guys in their tech support team and I worked with one gentleman his name alludes me but I have to say that they are phenomenal with their follow up and their knowledge base. if I was to ever buy a product aftermarket product I would go with JP cycles they know their s***.
June 1, 2020
Works like a ECM on my 2012 Road Glide should. I like the way you can hook my laptop to it and go in and program it and see the readings for fuel management and all the other things you want to look at. Works well with the S&S 2 into 1 exhaust with the 18 mm oxygen sensors. Wish I would have put this in my bike a long time ago.
May 16, 2020
I love my new thundermax auto tuner we're having problems dynoing my bike before but the thundermax auto-tune on downloaded their Maps started to bike at tood itself and runs so much better A lot better throttle response a lot more horsepower a lot better idle and motor runs a lot cooler

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ThunderMax ECM with AutoTune Closed Loop System

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