Making a Limp Harley Hard Again

Making a Limp Harley Hard Again

Published In The April 2020 Issue Of Cycle Source

Article By: Corey Barnum

Photos By:  Craig (6PM) Harriman

This month’s tech article is about one fix on a Harley going into limp mode.  Our customer was having an intermittent problem with his 2009 FLHRP going into limp mode.  Limp Mode happens when there is a correlation error between the twist grip sensor, electronic control module, and throttle control actuator.  It limits the RPMS and throttle response of the bike.  Basically, it lets you limp the bike home or to a shop to get it repaired.

The first thing I do is pull all the diagnostic trouble codes. There are two ways of getting these.  The first is called the wow test.  It is done by holding the trip button down when you turn the ignition switch on. Make sure the run/stop switch is in the run position when doing this.

This is what your speedometer will look like when doing the wow test.  Each one of these letters represents a different system. Press the trip button once to switch categories. When you have selected the correct one, press and hold the trip button to get dtc (diagnostic trouble code).

After holding down the trip button in the power category, you see the trouble codes will start showing up. To see if there is more than one code, simply press the trip switch.  Make sure to record all codes as you cycle through them. When the part number for the component you are checking comes up, you have cycled through all the trouble codes for that category.

The second way to pull up trouble codes is with the data link connector, and some sort of software to read Harley’s electronic systems. There are many of these on the market.  We use Techno Research.

Here are all the codes that Techno Research was able to pull off the bike. As you can see, these codes are all historic. I’m only going to worry about the three pertaining to the bike going into limp mode. They are p1511, p2135, and p2176.

When I see code p2135 that tells me that I am having a problem with the throttle control actuator.  Harleys made from 2008-2010 with the electronic throttle had their terminals made out of inferior metals and had a problem with fretting. I begin taking off the air cleaner housing to expose the induction module.

Here is what your induction module will look like after the air cleaner housing has been removed.  As you can see in the picture, someone has already messed with these wires, so we will clean that up for them after the repair.

After disconnecting the harness from the induction module, I give each wire a slight tug to make sure none of the wires are broken. Don’t pull on them to hard, because you could cause the damage.

As you can see in this picture, one of the six wires is broken.

To remove the wires from the housing, the first thing is to take a little screwdriver and pop the secondary lock. You don’t have to remove this completely, just pull it up until it moves freely in the connector.

Once the first lock is released, you will then have to get something through the connector to get the primary lock released. A paperclip or a safety pin will work. As you can see, I was using a safety pin. Just push it in until you feel it press on the internal lock and gently pull the wire out from the back side.

With all the wires removed from the connector, I cut all the old terminals off and strip back the wires for the revised ones

From 2008-2010 Harley had a problem with these terminals fretting.  In 2011 they change the metal, and this eliminated this problem.  Here is a picture of the revised terminals.

Using the proper tool, I now install the revised terminals on all 6 wires.

With all the wires repaired, I then put the air cleaner back on. When that is complete, I clear all the diagnostic trouble codes and take the bike out for a road test. No more problems occurred on the test ride. This Harley has now gone from limp to hard.

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