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Harley-Davidson Electronic Throttle Control

teve Bohn
February 12, 2009
Filed under Harley-Davidson Motorcycle Road Tests: Reviews on Harley Motorcycles, Motorcycle Parts + Accessories + Luggage: Reviews

In 2008 Harley-Davidson introduced a new throttle system called Electronic Throttle Control (ETC), which eliminates the throttle cables connecting the throttle and the throttle body and replaces them with an electronic connection. ETC is standard on all 2008 and 2009 touring models, including CVO touring models.

Four years ago a group of engineers set out to clean up the appearance of the big bikes’ handlebars. One item that really caught their eye was the throttle and return cable. Modifying or replacing them would go a long way toward making the bars less cluttered. The engineers also wanted to increase reliability and preciseness in the new system. The path they chose was built on relationships they have with both Delphi Corporation and Magneti Marelli.

When the project began, Magneti Marelli already had over one million electronic throttles on the road, mostly in over-the-road trucks operating in Europe. Delphi’s contribution would come in the form of technology and electronics used to enhance the system.

Harley-Davidson Electronic Throttle Control

Harley-Davidson Electronic Throttle Control

The ETC system consists of two main components; the throttle-grip sensor, and the throttle-control actuator. The throttle-grip sensor is made by Delphi, and the throttle-control actuator is manufactured in South Carolina by Magneti Marelli. The throttle-grip sensor is a cylindrical component housed inside the right end of the handlebar. The unit is spring loaded to return to idle, and includes two sets of magnetic sensors that send signals to the electronic control module. The throttle-grip sensor is keyed to the handlebar with a series of notches cut into the bar that mate with bosses on the throttle-grip sensor. The throttle-control actuator includes a geared, permanent-magnet DC motor, and two sealed automotive-style throttle-position sensors mounted to the side of the throttle body. The electronic control module, which controls the motorcycle’s electronic functions, allows the throttle-grip sensor to communicate with the throttle-control actuator.

Motorcycle enthusiasts are no different from the rest of the population when it comes to change; some embrace it, while others resist it. ETC immediately raised concerns among the latter group. What if the throttle sticks open? What if it sticks closed? Can I change out the handlebar? How much more will this cost me in the long run? For the answers to these questions, and to learn more about how ETC works, I contacted Portfolio Architect Lance Onan and Senior Project Engineer Scott Koerner at Harley-Davidson.

One of the first and most important items addressed by Lance was the redundancy built into the system. He explained that there are two separate sets of magnetic sensors housed in the throttle-grip sensor, two throttle-position sensors at the throttle body, and two separate circuits built into the electronic control module. “As the throttle is opened by the rider, the sensors sense the presence of a magnetic field. This is known as the Hall effect—there are no contacts, brushes, or wipers to malfunction. At the throttle body, two separate throttle-position sensors compare the position of the throttle plate and verify that it is in the position called for by the magnetic sensors in the throttle-grip sensor. There is a control loop built in to the electronic control module that provides constant feedback as it monitors the system some 200 times a second. The system looks at both the bottom (throttle-control actuator), and at the top (throttle-grip sensor), so there’s redundancy at either end. The system is constantly comparing those conditions and looking for a failure mode.”

Harley-Davidson Electronic Throttle Control

Harley-Davidson Electronic Throttle Control


If for any reason a failure is sensed, the system will go into one of three failure modes, Scott explained. “If you lose one signal from the Hall effect sensors the system goes into a failure mode called limited-performance mode. In that mode the throttle response will be somewhat slower; it’s going to limit how far the throttle plate will open, you’re not going to get full performance, and cruise control will not work since the sensor itself no longer has redundancy. It also uses the brake input as a redundant—if you are on the brake it will drive the throttle plate to near idle. If you then lose the other Hall effect sensor signal and the electronic control module is unable to determine what the rider wants to do, it goes into a forced-idle mode. In this condition it controls the motorcycle’s idle speed and will allow it to give just a little more adjustment than the pure idle control. It will give some spark advance based on engine speed so that when using the clutch you are still able to get the vehicle home, but it will be at an extremely slow speed—we don’t allow the throttle plate to open up and give you any unexpected power at all. This mode will allow a rider enough power under idle to get it up a few gears and get the bike moving. Providing even more safeguards is the limp-home mode that kicks in if you lose the DC motor or either of the throttle-position sensors. In this mode the engine will provide idle only.” If you find yourself experiencing any of these situations, a trip to the dealer is imperative.

I asked if it were possible for the system to open or close the throttle plate without the input from the rider. “The only way that could happen would be if the grip were actually rotated and held in a particular position,” Scott told me. “If you look at the possibility of short circuits causing something like that where it looks like it’s as open as it can be, the ECM ignores that. If the voltage gets over a certain threshold it (the electronic control module) doesn’t believe that input any more because it knows that can’t happen through normal actuation of the sensor; that can only happen through an electrical fault.”

ETC has various advantages over traditional systems. It requires no maintenance, there are no cables to adjust, lubricate, or replace, and the system has an indefinite life span. Throttle positioning is far more accurate than it is with a cable system. This is beneficial for EPA testing as one of the tests involves riding the motorcycle on a dyno to simulate real-world conditions. In this situation it’s possible to hold the bike at a particular rpm more easily and accurately than before, leading to cleaner tailpipe emissions.

ETC interfaces with cruise control differently from the previous throttle cable set-up. Prior to 2008 there was a separate cruise-control module that operated the throttle plate by means of a long cable. The new system eliminates the module and operates the throttle plate via the electronic control module. The cruise control on ETC models works far better than on previous units; gone is the surging and variation in speed as the system is engaged or encountering hills. It operates very smoothly, and changes in engine rpm are barely perceptible.

Built into the system is a reset function. If the ignition is turned off with the throttle in a position other than 0 percent throttle, the system wants to use a higher rpm as the new idle speed the next time the engine is started. If you shut the bike off at 1,800 rpm, the next time you start the engine it will use approximately 1,400 as the new idle speed. To keep this from occurring you can reset the idle by turning on the ignition switch until the fuel pump cycles on and off, then turning off the ignition. Repeat this three times and the idle speed will be reset to normal, 1,000 rpm.
The ETC system only works with handlebars that have the notches that mate with the throttle-grip sensor; it will not work on traditional handlebars. Harley offers various handlebar bends for the new system. For certain applications they also offer a throttle-grip sensor with longer wires (43-1/4 inches long, Part No. 32308-08, $89.95), which connects directly to the stock wiring harness without an extension harness. Swapping grips on bikes equipped with ETC requires the purchase of grips designed specifically for ETC applications.

In the real world the ETC feels much the same as a traditional throttle. There are some subtle differences, however; the perception of these differences seems to vary from person to person. Most of these perceptions have to do with throttle response at lower rpm. What I find most notable is the quick drop-off in rpm when I back off the throttle at slower speeds and when shifting gears. When rolling off the throttle, the engine slows more quickly than I’m used to, which has a tendency to pitch my weight forward a bit. This can also be felt when hitting bumps that cause my hand to roll the throttle on or off, causing the bike to jerk a bit. These are not major issues, just something to be cognizant of when operating the motorcycle. Another mechanical difference is the fact that the throttle grip is returned to its zero position with a built-in spring instead of springs mounted on the throttle body. Since the new spring does not have to overcome friction and wear of the cables, it snaps back with more authority and has a different feel than the previous system.

While none of these conditions are particularly earth shattering, they will take a little time to get used to. Some riders will be barely able to perceive the differences between ETC and a traditional cable setup, while others will notice a difference as soon as they roll on the throttle for the first time. No matter what your take is on this, you will have to go with it if you want to ride a new touring machine. Considering Harley has a tendency to introduce new features on a limited basis before introducing them to the entire line, I would expect to see ETC (as was the case with EFI) to be standard fare on all of Harley’s bikes in the not too distant future. So roll with it and enjoy all the benefits that come with this new technology.

Comments

27 Responses to “Harley-Davidson Electronic Throttle Control”

  1. Dennis on January 19th, 2013 11:31 am

    What actually causes the failures to occur with this throttle system? Does a sensor go bad or the entire system fail? My dealer “didn’t find anything wrong”? However it happens intermittenly with no warning. Any suggestions?

    [Reply]

    Dennis Reply:

    Dealer claims they can only check it while it is in failure or they have “no clue” so who does? Got a feeling HD better jump on this quick before all the lawsuits start piling up. I just want mine fixed while still in 5 year warranty!

    [Reply]

  2. Greg Smith on February 8th, 2013 4:20 am

    Hi, my name is Greg Smith and I live in Denlilquin, Australia.  I had a stroke in 2009. 
    I have little use of my right arm and I have a 2008 FLHCU Ultra Classic Harley Davidson. Firstly, I have to go from right to left throttle (fly wire).
    The problem I have is that when the fly wire is put on the left hand side it has to be throttled forward rather than the normal backwards.  Do you have any suggestions as my mechanic says that this will be problem. Any help would very appreciated.

    Cheers

    Greg Smith.

    [Reply]

  3. Greg Smith on February 11th, 2013 11:09 pm

    I my name is Greg Smith and I live in Denlilquin, Australia.  I had a stroke in 2009. 
    I have little use of my right arm and I have a 2008 FLHCU Ultra Classic Harley Davidson. Firstly, I have to go from right to left throttle (fly wire).
    The problem I have is that when the fly wire is put on the left hand side it has to be throttled forward rather than the normal backwards.  Do you have any suggestions as my mechanic says that this will be problem. Any help would very appreciated.

    Cheers

    Greg Smith.
    I h

    [Reply]

    Ale Reply:

    Hi Greg! I’ve the same problem like you. I’m driving a Sporty and I’d like a Touring Model with new connectet brake system. Did you find a solutions to move the ETC throttle on the left side?

    Cheers.

    Ale

    [Reply]

  4. Luke on July 8th, 2013 7:55 am

    I have a 2008 FLHTCU with ETC. The bike has 20,000 miles on the clock and is going to my dealer for the 3rd time for a problem with the ETC. This time it started acting up 360 mi. from home on a Sunday. Was able to override the system by cycling the ignition. Made it home ok but am fed up with this system. Does anyone know of a recall from HD? Have you a similar story?

    [Reply]

    mike Reply:

    my bike has 37000 on it, be crusin about 55 and lose my revs, stays running but dose not rev up , let it set for 5 mins and it ok

    [Reply]

  5. dale on August 5th, 2013 5:00 pm

    Luke..my bike is the same year model and I have 96,000 and started having throttle problems about 4 months ago. It appeared to be when I tried to override the cruise when I would have the cruise control set and then when I wanted a little more speed to get by a vehicle I gave it throttle without disengaging the cruise control (this is what I thought was the problem), it turns out that was just a coincidence. All of a sudden the engine would just go to idle, it did it three times today so now I’m taking my bike to HD and they are supposed to be able to diagnose based on the bikes “engine light history” but we shall see.

    [Reply]

  6. Bill on September 12th, 2013 12:12 pm

    I have an 011 Road Glide Ultra and have had nothing bu trouble with the Throttle by wire. First three times it would go full throttle, all three times were while performing low speed manuevers to the left. alos had issues with throttle going to idle speed with no throttle response. I removed the green plug and hard soldered the wires. Worked for 6k miles, unitl day before yesterday, now going to idle with no throttle response. Out of warranty now. I’m stuck. Going to trade in it in for something with cables. This setup is just not safe!!!!

    [Reply]

  7. Bill on October 29th, 2013 7:12 am

    My local dealer has really been helping me out. They called the motor company and the decision was made to replace the throttle body. Which was done last week at no charge to me. So, to date, all sensors have been replaced, the ECM has been replaced, the ABS module has been replaced. A Screming Eagle twist grip harness has been installed. and of course the throttle body. All that’s left is the main wring harness. If it happens again, I’m enforcinng the lemon law, The dealer that has been working with me, agreed with the lemon law enforcement if I have more trouble.. Also had to replace my front wheel bearing (13k miles). turns out between 08 and 011 wheel bearing were bad (made in India) in 012 they were upgraded! no made in south Korea.

    [Reply]

  8. Manoj Jacob on October 30th, 2013 4:18 am

    Hi
    Good to hear that there are dealers who live the brand and go the lengths to ensure that the rideis in optimum working order.

    In India it looks like the dealer is the king and any one raises any questions with the quality of service li. I did gets severed iff and does nt get any form of support even though it is a certified Authorised dealership in Bangalore India.

    Thus is one brand of motorcycle where I cannot buy a spares from a local Authorized dealer what a shame and the best part is that the blokes in USA are keeping quite there is loads of issues here and the wonderful brand HD image us getting screwed we a bunch of 100 bikers across the country are looking to get to gethrr

    [Reply]

  9. Dugan Sewell on May 2nd, 2015 6:14 pm

    For a while now, when I roll off to disengage cruise, my throttle ratchets. Today it started ratcheting when I roll on. Is there any way to adjust the gear on the throttle?

    [Reply]

  10. Diego Palerma on May 11th, 2015 8:27 am

    I have a 2008 flhx Street Glide two or three times a season i loose throttle control engin still run when i turn the bike off for thirty seconds the i gain control to the throttle again, does any body have this same problem let me know thank you and ride SAFE.

    [Reply]

    jack Reply:

    yes had that problem today , shut off for 1 min. all ok. Happen 1 year ago . going to pull tsb plug and clean and do dialectic grease hope works for another year

    [Reply]

  11. alberto gonzalez on May 22nd, 2015 7:47 pm

    my 2008 flht has icon key for alarm illuminated when in motion need some kind of help

    [Reply]

  12. Steven Keller on June 8th, 2015 6:28 am

    I have a 08 Ultra with 25000 miles. I just started having this problem wirh the electronic throttle control. Was out on the road, acted up twice. Came home , looked it up on Fix My Hog. They said to clean and lube pin connector. Did that, did not solve problem. I tried turning ignition off and on three times. Did not work either. Disconnected battery to reset computer. Took it for a test ride,so far. so good.

    [Reply]

    Mike Reply:

    hey is still working for you?

    [Reply]

  13. mike m on June 15th, 2015 4:32 am

    Hello Fellow riders I AM DOWN HERE IN PALMDLE CALIFORNIA and I have had that same throttle problem twice now. and it is pissing me off because I have had to pay out of my pocket to have it towed to the Harley dealer to basically have them give me a bill but no explanation as to the problem. and on top of that the first time it happened I had another issue that they were clueless about witch happened to be my butterfly in my throttle body was stuck closed to were apparently you couldn’t just push it open with your finger you had to lightly tap on it. and of course Harley had no explanation for that issue either so basically my friends what I am getting at is if it were to take us all to get together to hopefully just maybe get a recall going .if your with me comment back !!!!!

    [Reply]

    Mike Reply:

    i am with you

    [Reply]

  14. Jim Rigney on June 20th, 2015 6:33 am

    Just started having a problem with the throttle all of a sudden it goes into a high idele and I ha e to stop. Restarted the bike and all was OK but within a mile same thing. Sat ten min and got her going and rode home 30 miles in a hard rain and she did OK. I have a 08 ultra classic. Is this a high dollar fix and how hard is it to do I know how to fix something’s . any advise would really help. Thank you Jim

    [Reply]

  15. david witt on June 22nd, 2015 10:25 pm

    Can I cut my handlebars 3/4 of an inch, throttle side, if I notch it as it was?

    [Reply]

  16. Raymond Foret on July 12th, 2015 1:00 pm

    I have a “new to me” 2013 Harley Ultra, it has 11,000 miles on it and worked fine until today. I took a 15 mile ride to the hardwear store and parked my bike in the lot, it was hot, in the 90’s. Upon my return I started my bike normally and went to pull into traffic when I had no throttle, the grip just turned in my hand and nothing but an idle was produced. I had enough momentum from the initial start to pull alongside the road and stop. I had no throttle response whatsoever, it felt like the entire grip just turned in my hand, round and round. I noticed my clutch grip did the same thing, just turned so easy I could have pulled the grip right off the handlebar. I rotated the throttle until it felt like it had a slight resistance and still no response. I thought because the left grip was so loose that the GRIP ITSELF was not in position, so I TAPPED ON THE END OF THE GRIP and all of a sudden I had throttle response again, THIS HAPPEND ABOUT 25 TIMES, LONG ENOUGH TO GET ME HOME. I stopped the bike in my garage and restarted it, there is a slight bit of resistance but it worked O K. I stopped it and restarted it with the same result only this time when testing the throttle limit it would stick at a high rpm. The one thing I did notice was that the throttle would NOT rotate as it did in the parking lot and I could not rotate the throttle BACKWARDS like I could in the lot. COULD THERE BE A PROBLEM WITH THE GRIP COMING OUT OF PLACE WITH THE THEROTTLE POSITIONING PLATE THAT IS SUPPOSWED TO RESIDE WITHIN THE HANDLEBAR CUT OUT? When the grips get hot (summer heat) can the grip slide out of position making the throttle come out of position? Right now the throttle grip does NOT do what it did in the hot parking lot because it is in a cool garage. Has anyone else had the same problem?

    [Reply]

  17. Mervin on July 22nd, 2015 7:05 am

    I have an 08 Ultra. Bought it 2 years ago with 34k on it. Started having problems with this ‘limp’ mode this spring. Took my bike in for it’s 50k service and dealer replaced pins and said it should be fine. It’s happened several times since without warning. Sometimes when I’m going through the gears and sometimes when I’m running at full speed. The other day it happened 3 times in 4 miles. It’s at the dealer now and they see the code where it lost throttle response but they do not see anything wrong with the bike. Said the throttle body unit could be replaced to see if it is the problem…but the throttle body on it checks out to be fine. I’m not paying $ 1,000 for someone to guess the problem. I shouldn’t have to pay at all to fix something that is clearly a problem across the globe with this system. Recall? I wonder how many used bikes with this problem gets traded in with no record of this problem, only to have the problem handed down to some poor sap like me who now has to front the problem from his own pocket? I want my Harley fixed…but if it can’t be fixed and the manufacturer won’t acknowledge the issue…my next bike may be native American.

    [Reply]

    jack Reply:

    call my dealer today about there problem and SAFETY on this throttle thing and limp mode he said there is still no RECALL, WE NEED TO START SUING HARLEY DAVIDSON

    [Reply]

  18. Raymond Foret on July 22nd, 2015 12:48 pm

    Mervin, I found a problem with my 2013 Harley Ultra throttle response. I think mine was caused by the throttle grip itself coming disengaged with the “fly by wire” throttle plate. The groves in the handgrip itself was not engaging the groves in the throttle plate in the handlebar itself. The throttle plate itself is not secured in my handlebar and is loose in the groves meant to house it. The time mine did it the weather was very hot and both handgrips were very loose on the bar. I found that if the whole throttle assembly is not in the right position ( must be all the way pushed on the throttle plate within the bar) and it is hot enough to expand the grip the connection between the throttle plate and the groves in the handgrip there is a much greater chance for the throttle grip to become disengaged and you will lose throttle response AND YOUR CONFIDENCE IN YOUR BIKE. I believe this is what happened with the previous owner of my bike. I found that the past owner had dropped the bike on the throttle side, there was no damage except for some paint scratches on the saddle bag under the crash bar and the engine guard. I found the whole right grip had been replaced but was not in the correct position on the bar. After finding some teeth broken on the inside of the grip I repositioned the grip and made sure the whole assembly was in the proper relationship with the grip itself. Make sure the grip rotates properly AND WITHOUT ANY STICKING SPOTS. Test the rotation of the grip MANY times without the engine being on, when confident it will not stick try it with the engine on, again make sure the grip returns to idle easily and by itself. Try this if you feel confident enough, it is not very hard to accomplish and will save you time money AND MAKE YOU MORE CONFIDENT IN YOUR RIDING ABILITY.

    [Reply]

  19. Tom miller on August 10th, 2015 1:44 am

    I have a new 2015 street glide and i use a vane and hines fp3 tuner true duals and slash cut slip ons. I noticed the tear cylinder dropping out at red lights. And was told its a feature i was un aware of and it could be dissabled by turning my grip forward well my grip did not go forward so i applied alot of pressure i heard a snap and low and behold it now rolled forward and dissabled the parade mode. But now ith bike funs like crap. Idle varies and front cylinder dont start firing unyil i turn the throttle about 1/4 turn . No matter what map i flash it is like the front cylinder needs mor throttle to start firing. I think theres a problem with it. I double check my camalignment because i installed s&s 585 easy starts. Opinions pleas i am considering buyin a new tps.

    [Reply]

  20. terry on August 20th, 2015 12:25 pm

    does my 2012 Harley triglide have the electronic throttle or is it cable operated thanks I want to change the handlebar grips bui I don’t know what to get thanks

    [Reply]

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