Does Error code U0121 cause error P0031 P0051
Thread Starter
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Tourer
Joined: Dec 2013
Posts: 380
Likes: 21
From: Colombia
Does Error code U0121 cause error P0031 P0051
Morning all.
Ok , I am having a huge problem resetting the bike, I have cleared the ECM and tried to clear the Error code U0121 but it will
not go away . I am putting the bike with an auto electrician tomorrow . I have read the other threads saying to check the small
wire to the speedo there error code U0121 comes up in 2 places. Under BCM and Spdy .
So if that problem is there does that cause the error P0031 AND P0051 , if the ECM is not getting the speed information
does it throw out the error code .
Is the speed a function in how the ECM calculates values ?
I am getting that the fuel injectors are open front and rear.
Now this was happening before i CHANGED to the dynovision powervision with the Target tune.
I was hoping installing these would rectify the problem .
I am NOT try to run the power vision target tune at this time , just run a normal tune with Wide Band sensors.
I am doing the Hammer upgrade. But if i cannot get the PV to work because of these error codes . I am STUFFED.
So would the U0121 code error cause the P0031 y P0051 errors ?
So is the lost comms to ABS and SPDY causing the problem ?
Regards Mike
Ok , I am having a huge problem resetting the bike, I have cleared the ECM and tried to clear the Error code U0121 but it will
not go away . I am putting the bike with an auto electrician tomorrow . I have read the other threads saying to check the small
wire to the speedo there error code U0121 comes up in 2 places. Under BCM and Spdy .
So if that problem is there does that cause the error P0031 AND P0051 , if the ECM is not getting the speed information
does it throw out the error code .
Is the speed a function in how the ECM calculates values ?
I am getting that the fuel injectors are open front and rear.
Now this was happening before i CHANGED to the dynovision powervision with the Target tune.
I was hoping installing these would rectify the problem .
I am NOT try to run the power vision target tune at this time , just run a normal tune with Wide Band sensors.
I am doing the Hammer upgrade. But if i cannot get the PV to work because of these error codes . I am STUFFED.
So would the U0121 code error cause the P0031 y P0051 errors ?
So is the lost comms to ABS and SPDY causing the problem ?
Regards Mike
Thread Starter
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Tourer
Joined: Dec 2013
Posts: 380
Likes: 21
From: Colombia
BTW . If i clear the ECM and then start the bike , the check light comes on after about 3 seconds.
Quick tip because i always forget this...when resetting the ECM you have to hold down the RUN button before you hit the ON/OFF button .
Quick tip because i always forget this...when resetting the ECM you have to hold down the RUN button before you hit the ON/OFF button .
Seasoned HDF Member
Joined: Sep 2017
Posts: 12,186
Likes: 4,908
From: England
U0121 Lost comm W/ABS
P0031 Front HO2S low/open
P0051 Rear HO2S low/open
If code U0121 is lost communication with ABS unit why do you keep referring to the speedo? If the communication was lost to the speedo you would get code U0156 Lost comm w/SPEEDO according to Fuel Moto.
Harley Trouble Codes (fuelmotousa.com)
Have you made any changes to the O2 sensors or the wiring to them?
P0031 Front HO2S low/open
P0051 Rear HO2S low/open
If code U0121 is lost communication with ABS unit why do you keep referring to the speedo? If the communication was lost to the speedo you would get code U0156 Lost comm w/SPEEDO according to Fuel Moto.
Harley Trouble Codes (fuelmotousa.com)
Have you made any changes to the O2 sensors or the wiring to them?
Thread Starter
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Tourer
Joined: Dec 2013
Posts: 380
Likes: 21
From: Colombia
Yes , I have installed the Dyno jet , wide band sensors .
I am trying to figure out if one error can cause another error .
So going to re install the original sensors , see if that helps .
Refering to the speedo , it was in another thread here when i was searching through everything
They said check the wire from the speedo .
So i am wondering if the wrong speedo input is screwing up the ECM and stopping it from working
I did notice the speedo dial was a bit slower ..i had them check it and clean it .
Wondering if it could be a snow ball of errors happening.
I am trying to figure out if one error can cause another error .
So going to re install the original sensors , see if that helps .
Refering to the speedo , it was in another thread here when i was searching through everything
They said check the wire from the speedo .
So i am wondering if the wrong speedo input is screwing up the ECM and stopping it from working
I did notice the speedo dial was a bit slower ..i had them check it and clean it .
Wondering if it could be a snow ball of errors happening.
Thread Starter
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Tourer
Joined: Dec 2013
Posts: 380
Likes: 21
From: Colombia
I am wondering when you clear error codes , Do you shutdown the bike after each error code , that means you shutdown the bike twice
if you have 2 error codes . go through the cycle twice ?
if you have 2 error codes . go through the cycle twice ?
Thread Starter
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Tourer
Joined: Dec 2013
Posts: 380
Likes: 21
From: Colombia
Thanks Andy , will try that again . Besides using the odometer to read codes , i also use a FP3 and and a Power vision .
Nothing has cleared the codes so far .
Nothing has cleared the codes so far .
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Thread Starter
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Tourer
Joined: Dec 2013
Posts: 380
Likes: 21
From: Colombia
Pls see " ABS problem on 2104 Dyna" by RossWG.
The second last entry is the exact same error codes .
https://www.hdforums.com/forum/dyna-...2014-dyna.html
The second last entry is the exact same error codes .
https://www.hdforums.com/forum/dyna-...2014-dyna.html
Stage III
Joined: Apr 2022
Posts: 3
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From: AZ
@MikeLaPlaya - did you ever resolve your issue? If so, what was the problem you were encountering? I am running into the same problem!
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