I ride my bike to work every day (about an hour each way). It has 107k miles. I typically do all of my own wrenching. In June, my ABS light stayed on. I hooked up my Power Vision to read the codes – it said open or shorted circuit in the front wheel speed sensor. I inspected visible wires but did not see anything, so I decided to ignore it until I was ready to deal with it (too busy all around at the time).

In late July, I was riding to work in the morning. Half way there, when I started out of a traffic light, the bike was surging – the power would drop out then come back. The engine light came on. I pulled off, shut it down and restarted in case something just needed to reset. Nope, still surging, needed to find somewhere to park it and remembered an independent shop just ahead and pulled in there. He didn't open till 11am, so I called and left a message.

I called my lady to bring a car so I could get to work and bring my Power Vision too. In addition to the ABS codes there were now Twist Grip Sensor codes. I have been having to work a lot of hours, didn't have time to mess with it and since it was at a shop, decided to let him check it out. He was busy and it took a week for him to get to it. We decided to go ahead and put in a new TGS. To expedite things, I went to the HD dealer and bought the part and took it to the Indy. He replaced theTGS, but the codes kept coming. He said he couldn't do any more for it, because he didn't have a breakout box for my bike to check electrical.

I checked the Power Vision, and instead of TGS codes, it now had Throttle Position Sensor codes and Throttle Control Actuator codes. I picked it up and took it to a friends place nearby, because driving it had been wacky, but going to the friend it did not act up or throw codes. I decided to drive it home, still no codes.

I mounted the Power Vision and drove it that weekend to see what was up. I could clear codes as they happened. The codes would always come when leaving a stop. The bike wasn't running bad.

I found and read up on bulletin T418A. I could bring up TPS 1 and TPS 2 voltages on the Power Vision. The voltages were within spec and did not falter if I wiggled the TPS molex connector.

I decided to continue testing commuting to work. I could get 2-3 codes in the first 10 minutes of riding, then be code-free the rest of the day. I could go a few days with no codes. Every once in a while, it would throw lots of codes and run terrible (the surging...power drops...and returns).

My thinking was that it was likely something bad in the throttle body electronics (TPS, TCA). I remembered a friend who had done a stage 4 on his new bagger a few years ago who might have the takeoff throttle body. He did, and I acquired a 2011 throttle body. I installed it and it solved nothing. Note: 2011 has a different throttle body part number than 2008-2010. It ran, but I could not clear the codes with the later model TB using the Power Vision. I also replaced the front wheel ABS speed sensor.

It was time to surrender. I hate taking it to the dealer, but I had run out of time and patience. I put my original throttle body back in and made an appointment at HD. I flashed my stock tune back in just in case… and took it in for my appointment a week later. I explained the full history and the service writer wrote something like: electric problem- ABS, Throttle….that's it. I was little aggravated that the dude had to go and try to blame the Power Vision….really? A flash tuner?

A few days later they called with questions and told me their diagnostics say Twist Grip Sensor. I said go for it but they better be sure, cuz it's new ...and if they are just guessing – I can do that.

The tech called my on Friday and said it was the TGS, and asked more about the ABS. I explained that I had replaced all bearings last winter and the speed sensor last week. I had not done anything to the bike at the time the ABS error started. He was still thinking the bearing and my bike should be done by the end of day. I called when leaving work – it would be ready for pickup, but I wouldn't be able to get there before closing.

Conclusion:
I went to pick it up today and was told it was NOT the twist grip sensor or ABS bearing. There was a broken wire in the main harness on each side of the steering neck causing the twist grip and ABS to error. So – no parts, just $600 labor.

So, if you are having electrical related problems on a high mileage bike, be sure to check the wiring around the steering head. He said if you felt along he wire, you could feel the break. It had tested OK at first, but it would make connection – and break connection as things moved.

 

I had codes p2135 and p1511 pop up on July 20 but the check engine light never stayed on, it was just on longer than normal at start up. Then on August 27 the engine light stayed on longer than normal at start up and then went out. I checked the codes and this time there was code p1511 and p2101. Both times there was the code for the tgs. But the bike ran great both times and didn't show any issues, just the codes. The tgs was replaced 3-4 years ago.

 

I work with electronics- and in an environment where they are freighted constantly.

90% of problems are a dirty connection...

and most of the rest are a broken connection.

I'll often suggest to frustrated riders that they shake the bike and whack the tires with a ball bat...manipulate the wiring harness.
That can narrow down problems.



Mike

 

Agree!
But would like to add that problems can appear after someone works in the area. My first question is to ask they had done any recent work on the bike.
FWIW, Changing parts gets expensive without correct diagnostic procedures, especially with electronic parts. Glad to see you got her going, even though it was costly and frustrating for you, its a relief when its finally fixed.