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DTC on 2011 FLHTK

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Harley38

Active Member
Hi All,

I have a question. I have two codes that come up when I check the ECM/ICM: P0134 and P0154. P0134 is front O2 sensor inactive and P0154 is rear O2 sensor inactive.

I read through posts similar to this, but it seems everyone had a check engine light on, bike not running well, etc. I do not have a check engine light on and bike is running well.

The only reason I went to check DTCs was to see what was there, if anything.

So my question is would the sensors be turned off and is this bad? Last thing I had done to the bike was a Dyno tune by the dealer about a year ago. I have a SEPST on the bike.

I am not familiar with the functions in a SEPST and if turning the sensors off is even an option.

I appreciate everyone's feedback
 
If you mean SEPST = SE Pro Super Tuner and you do not have any add on black boxes or fuel enrichment devices, those codes should never appear. Check to see if the O2 sensors are still connected to the wiring harness. Each O2 sensor has about a 10" pigtail lead on it. The front O2 sensor connects in the plastic box below the voltage regulator. Do you still have the tuning dongle.
If you do, is it black or orange in color.

If both O2 sensors are currently hooked up and are not unplugged, clear the error codes. Reboot the ECM and make sure you see "none" in the display when you recheck it. Ride the bike and see if the codes return. Those are codes that will not appear instantly. Ride the bike on the interstate at part throttle cruise speeds for a good 10 minutes.
 
Hoople...thanks for the speedy reply.

Yes, I have Screamin Eagle Pro Super Tuner - 32109-08B; Orange Dongle, no other fuel enrichment device.

They look connected to the sensor itself, I will check if they are connected to the wiring harness, clear codes and take a ride.

I will keep you posted, thanks :D
 
I went and checked connections at both ends of the sensors, everything was good. I even unplugged and plugged back in the O2 sensor plugs at the wiring harness.

Cleared the codes on the ECM and went for a 20 minutes ride on the highway. 10 minutes out and 10 minutes back with my speed between 65-70 mph.

Got home, let the bike sit a couple minutes, checked codes all clear! :D

I forgot to mention I did clear codes yesterday and did the same process, except check the sensor plugs on the harness. So, not sure why things cleared, but they did, and that is cool.

Thanks again Hoople! :D
 
That's good. Keep your eyes on it for a while. Those codes can sometimes take a while to post.
 
Interesting, if these codes don't reappear, why would they register? Do you think someone (service tech, or???) ran bike w/them disconnected for a bit, or maybe faulty sensors (both)???
 
Iceman24 said:
Interesting, if these codes don't reappear, why would they register? Do you think someone (service tech, or???) ran bike w/them disconnected for a bit, or maybe faulty sensors (both)???
Click to expand...

It's hard to say. The dyno tune was done about a year ago. I would think by now 50 clean cycles would have happened, which should have cleared out any historical codes caused by the dyno tune. It's almost like a new current code is refreshing the historical every so often. Why on both sensors is a good question. There is a breathing hole on the back side of O2 sensors. So O2 sensors can be ruined by hitting the external exposed portion with solvents, silicone, cleaners etc. It's far reaching but always possible.
I would try to check the error log prior to 50 cycles so it can't clear a historical on it's own.

There is just not many ways to explain it that I can see. A pair of sensors being bad/sluggish or the firmware in the ECM being corrupted in some way could do it.
If you were really wanting to know the answer, you can view the toggle speed (switching time) of each O2 sensor using a scope. It would be very easy to do and it would tell you a bunch as to what was going on.
A good switching time is normally around 1 HZ clean of any erroneous noise.
 
Thks Hoop - as always, your electrical knowledge is much appreciated. I have my sensors capped w/the GEN3 so no problem(s) for me, but seemed odd to have these coding on a new ride, but hope OP's problem is fixed...
 
Hoop and Ice....thanks for all the good info and questions. I haven't been back on the bike since Sat, weather here is rainy and probably be another week until I can ride do to my schedule.

I will keep an eye on the codes. After a good ride or two I will check the codes again and post.
 
Well the codes came back :( I probably rode 200 miles or so this weekend off and on. When I got home I checked for codes just to see and there they were. Bike is still running fine and no check engine light.

So, I will be calling the dealer and get it in for them to troubleshoot, but was curious if there would be something in the SEPST software that would allow for the O2 sensors to be disabled?
 
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