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ThunderMax ECM With AutoTune Closed Loop System
ThunderMax ECM With AutoTune Closed Loop System
ThunderMax ECM With AutoTune Closed Loop System
ThunderMax ECM With AutoTune Closed Loop System
Made in the USA
Read ( 32 ) Reviews

ThunderMax ECM With AutoTune Closed Loop System

J&P Cycles Part Number: 126-888

Manufacturer Part Number: 309-562


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Important Fitment Note

Requires use of exhaust with 18mm sensor bungs or headpipes need to be modified to accept 18mm sensors.


Description for ThunderMax ECM With AutoTune Closed Loop System

The ThunderMax ECM With AutoTune Closed Loop System is the high-tech way to manage motorcycle performance. It mounts conveniently in place of your factory ECM and plugs into your existing harness, and uses a closed-loop control system to continuously self-adjust and properly tune the motorcycle's air/fuel ratio for all riding conditions. The ThunderMax has hundreds of maps available to download for your bike. Choose based on model, engine size, exhaust system air cleaner, pistons, cams, and more. Then, load the map of your choice and the integral auto-tune will do the rest. You can adjust the idle speed, rev limit and speedometer calibration, front and rear cylinder AFR maps, ignition timing (spark) maps, and startup maps, all without dyno tuning. It works with all popular exhaust systems, is compatible with high-performance camshafts, and supports turbo, nitrous and supercharger applications. The software allows live monitoring, recording and examination of diagnostic codes and datalogs including number of starts, engine temperature and RPM operation. Easy installation and tech support, free software and updates included. Includes ThunderMax ECM with Auto-Tune Module, plug-in harness and two wide-band sensors, TMax software and communication USB cable, Quick-Start Easy Install and comprehensive user's manual, technical support and free software and updates. Will require the use of an exhaust system with 18mm sensor bungs or head pipes must be modified to accept 18mm sensors.

• Mount in place of factory ECM

• Self-adjusting

• Hundreds of maps

• Auto-tune

• Compatible with most exhaust systems

• Use with high-performance camshafts, turbo, nitro and superchargers

• Monitor, record and analyze diagnostic codes and stats

• Free firmware, tech support and updates

• System designed to work with 18mm O2 sensors

Product Specs

Product Specs for ThunderMax ECM With AutoTune Closed Loop System

Manufacturer Part Number:
Open or Closed Loop:
Sold in Units:
Warehouse Part Number:
With/Without 02 Sensor:
Fitment Note:

Requires use of exhaust with 18mm sensor bungs or headpipes need to be modified to accept 18mm sensors.

Fitment Questions?

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

Compatible Models

Harley-Davidson® Models

  • Touring Electra Glide Police FLHTP : 2014–2016
  • Touring Electra Glide Ultra Classic FLHTCU : 2014–2016
  • Touring Electra Glide Ultra Classic Low FLHTCUL : 2015–2016
  • Touring Road Glide FLTRX : 2015–2016
  • Touring Road Glide Special FLTRXS : 2015–2016
  • Touring Road Glide Ultra CVO FLTRUSE : 2015–2016
  • Touring Road Glide Ultra FLTRU : 2016
  • Touring Road King Classic FLHRC : 2014–2015
  • Touring Road King CVO FLHRSE6 : 2014
  • Touring Road King FLHR : 2014–2016
  • Touring Road King Police FLHP : 2014–2016
  • Touring Street Glide CVO FLHXSE : 2015–2016
  • Touring Street Glide FLHX : 2014–2016
  • Touring Street Glide Special FLHXS : 2014–2016
  • Touring Ultra Limited CVO FLHTKSE : 2014–2016
  • Touring Ultra Limited FLHTK : 2014–2016
  • Touring Ultra Limited Low FLHTKL : 2015–2016
  • Trike Freewheeler FLRT : 2015–2016
  • Trike Tri Glide Ultra Classic FLHTCUTG : 2014–2016
Customer Reviews

Customer Reviews for ThunderMax ECM With AutoTune Closed Loop System

Overall Rating

5 out of 5 stars (based on 32 reviews)

5 stars (28)

4 stars (4)

3 stars (0)

2 stars (0)

1 star (0)

0 stars (0)

BILLY on 12/20/2019

Quality and install is great still trying to find a tune that matches my set up

CAMERON on 10/14/2019

I was having misfiring issues and loss of power at low RPM with my bike for years. I took it to Harley and they said it was fine, then I took it to another shop who knew it wasn't right but couldn't find the problem. I read that there are issues with some stock ECM's. The ThunderMax was the best investment to replace my stock ECM and customize my tune. It runs like a new bike!

JACOB on 9/5/2019

easy to install and load base map haven’t got bike in a day I yet but tuning software is easy to use but could be set up a little better

Swifty67 on 7/22/2019

Easy to install and easy to get started with

WES on 6/17/2019

The hardest part is finding the right tune. After that you HAVE TO CONNECT to the computer after riding it a few hundred miles and set the learned as the base. After you shut off the bike it goes back to the base tune and relearns the fuel air ratio. I’m getting great mileage with this new computer and have good power.

TROY on 6/3/2019

It fit like OEM on my bike. I have yet to use the tuning feature. A little pricey but worth it. Program was easy to download and use.

AARON on 5/23/2019

Spend the money. Nothing else compares.

RICHARD on 5/7/2019

So far so good?? More money than I wanted to spend but I really like the auto tune. Installed and tuned it all myself.... can't say that it didn't make me nervous, but it runs great!

TERRY on 5/5/2019

Great purchase and straight forward hookup. TMax tech was great to work with and helped find the perfect map.

ROBERT on 4/15/2019

Installation and set up was very easy. So far it is working great. I look forward to learning and using the system to improve performance in the future.

Important Product Notes

Not legal for sale or operation in the state of California.ÿCheck with the U.S. EPA and your respective state and local regulations to confirm emission compliance. 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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