Trouble code P0171 won’t clear

[Hoppy]

My 2012 RT SM5 got a P0171 code which is tells me it’s running lean. Throttle body was replaced under warranty. Cleaned throttle body this spring. Tried all the key, headlight switch, etc tricks but wouldn’t clear. Parked bike over night and checked again without starting engine. It’s still showing the code. Shouldn’t that reset? Only active codes are shown so how can it be an active code if I haven’t started the engine?
Pulling out the little hair I have left!

 

[Chupaca]

Curious...

Do you remove the key when you shut down and give the computers time to shut down..? If so try disconnecting the battery. Did they change the vacuum hoses to the throttle body if not change them same length using silicone hoses...:thumbup:

 

[Snowbelt Spyder]

My 2012 RT SM5 got a P0171 code which is tells me it’s running lean. Throttle body was replaced under warranty. Cleaned throttle body this spring. Tried all the key, headlight switch, etc tricks but wouldn’t clear. Parked bike over night and checked again without starting engine. It’s still showing the code. Shouldn’t that reset? Only active codes are shown so how can it be an active code if I haven’t started the engine?
Pulling out the little hair I have left!

Hey Hoppy. Stop pulling your hair and all of those other things. The code is there because of the way that it is set. If a lean condition occurs, as sensed by the 02 sensor, the ECM enrichens the fuel correction - commonly called fuel trim - in order to try to correct the lean condition. Again, that feedback comes from the 02 sensor. The new value of fuel trim is stored in memory so that it doesn't have to do it all over again every time you start up. There will be no code if it can be corrected. If the lean condition can't be corrected and the fuel trim reaches the end of it's adjustment limit, that is what sets the code. So, even though you haven't started the engine, that value of fuel trim is stored in memory and the code is still active.

Both the lean and rich codes work the same way. It's the value of the fuel trim that sets the code. Standard Bosch stuff.

Two things have to happen - you have to correct whatever engine related issue caused the lean condition in the first place, and you have to ride around for awhile in various speed and rpm conditions allowing the ECM to re-adjust the fuel trim away from the limit, so that the code will reset. Typically, you'll see the light out the next time you do a cold start if you've been successful. If not, then you still have the problem.

Since you have an SM5, and since this code is for the front cylinder, a potential problem that jumps to mind is that vacuum hose on the right hand side of the front throttle body that goes to your clutch vacuum assist solenoid. Check for cracks and that it is even installed correctly. Of course you want to check and replace as necessary, the two vacuum hoses on the left side that go to the MAP sensor, if they have cracks or are installed - especially the front one - which is hard to get to and goes to the front cylinder. A bad 02 sensor, or fuel injector is always a possibility, too, but seldom occurs.

How long has this been going on?

 

[Hoppy]

Thanks for the help. Just started on last ride. Check engine light came on. Then the check engine symbol at bottom on dash screen came on and off. Then the whole screen showed “check engine”. But both came on and off while the check engine light stayed on. Bike ran fine on short ride home and temp gauge didn’t increase but the check engines on screen flashed on and off the entire ride home. Seemed to start immediately after hard braking (car pulled out in front of me) but I doubt that had an impact. Will pull covers and replace hoses. I work on all our bikes so I’m capable of performing the repair. Thanks again and I’ll update after hose replacement.

 

[Snowbelt Spyder]

Thanks for the help. Just started on last ride. Check engine light came on. Then the check engine symbol at bottom on dash screen came on and off. Then the whole screen showed “check engine”. But both came on and off while the check engine light stayed on. Bike ran fine on short ride home and temp gauge didn’t increase but the check engines on screen flashed on and off the entire ride home. Seemed to start immediately after hard braking (car pulled out in front of me) but I doubt that had an impact. Will pull covers and replace hoses. I work on all our bikes so I’m capable of performing the repair. Thanks again and I’ll update after hose replacement.

Yeah, I can't think of anything that hard braking would trigger. Your code is the key to it all. Most probably caused by a vacuum leak, but there could be other reasons. Check vacuum leaks first including the boot that the throttle body is mounted in.

The vacuum lines on the left side are fairly straight forward. The front line is a bit of a struggle. They both need to be the same length - 85mm long. 2.8mm - 3mm ID works fine. Anything larger in ID and they fall off. Smaller and they won't go on. The right side is going to be a pain because this all sits behind and under the air box. And if you follow that clutch line down towards the clutch, you will come to the actual clutch vacuum assist solenoid. It does have an open port on it. That's a vent port in order to remove the vacuum from the clutch cover when you release the clutch handle. So the open port is normal., However, it shouldn't be continuously sucking air when the motor is running. You can start up and check that, too. You will also find a check valve in the line.

 

[Hoppy]

Thanks for the additional info. I cleaned the throttle body 2k miles ago (yes I used throttle body cleaner) so I have removed the air box and I understand how much work this may be. Fortunately I have skills and tools required. Hopefully the vacuum hoses will fix the problem. May not get to this project for a few days but I will definitely let you know the outcome.
Once again Thank You for the help.

 

[Hoppy]

Where did you find 3mm hose. None of my local auto parts stores carry it? I can get it online but must buy 25’ and wait for shipping. 1/8” is available but it’s 0.007” larger. Could I possibly use that and snug it down with a cable tie?
Once again thanks for the help.

 

[Hoppy]

Never mind. Found 7/16” hose. It’s 0.001” smaller than 2,8mm. Goes on easy enough. Now put it all back together and test ride.

 

[Snowbelt Spyder]

PM sent.

 

[Hoppy]

Replaced hoses and no change. What next?

 

[SpyderAnn01]

Fuel filter maybe?

 

[Dgdecker]

Hoppy, I had code P0172 reappear after several dealer fixes and resets. Now mine was 2014 RTS with 1330 motor. Problem ended up being valve timing which required fixtures from the factory to properly adjust. 2000 miles later code has never reappeared.

 

[Hoppy]

I replaced that as well. Since it’s front cylinder only I think it’s not the filter as it feeds both injectors. I think it’s an injector or O2 sensor. Got detoured by an accident in the Black Hills and ran the fuel very low. Gonna clean the injector. If that doesn’t work I’ll move on to the O2 sensor. Bike runs fine with no oil pressure light and low engine temps. Think it’s more of an emissions type issue.

 

[Hoppy]

Ran the bike with injector cleaner in the gas. p0171 cleared but P0174 popped up. That is lean rear cylinder. So looks like it’s not the O2 sensor. Will run bike more and see if new code clears.

 

[BLUEKNIGHT911]

Ran the bike with injector cleaner in the gas. p0171 cleared but P0174 popped up. That is lean rear cylinder. So looks like it’s not the O2 sensor. Will run bike more and see if new code clears.

How injector cleaner did you use ???? …. that can be powerful stuff …. if you got the good stuff …. just a thought ….. good luck …. Mike hyea:

 

[Hoppy]

Final update. Codes have cleared!
Ran 1/2 tank of gas with injector cleaner and all the codes are gone.
Thank you all for the help!

 

[Hoppy]

I used Lucas Upper Cylinder Lubricant with Injector Cleaners. I have used this in my truck and Harley for many years. I bought a large bottle (32 oz for $11.98) and mixed 6 oz in a full tank of gas. It took running 1/2 a tank ( approx 60 miles) to clean the motor enough to clear the codes. I also cleaned the throttle body while I had the air box removed but that alone had no effect on the codes.

 

[Andrea Cook]

Hi folks. We're having a similar problem with our SM5 2011. It initially happened a little over a year ago and we needed both O2 sensors replaced as determined by the dealer, within two weeks of each other in the fall. Again this past summer we've had the issue reappear. P0171 code then the P0174 code sometimes individually and then both at the same time. So far we tried changing the air and fuel filters (no change), then replaced the purge valve (recommended by another dealer and had the codes reset through BUDS system at dealer). Two days later the codes were back, sometimes both or just one. Ran cleaner through the injectors, traced and tested the wire from the purge valve to the ECM (checked for continuity and corrosion), checked all ground connections (again recommended by dealer) and ran more cleaner through the system with no change. We've checked visually the vacuum hoses and nothing was obvious. Looking to replace the hoses next, I guess. Through discussion with dealer they have no idea what could be wrong and suggest to drop it in and they'll "pick at it" and see what comes up......doesn't provide much confidence. Bike only has about 25,000 miles on it. Any thoughts or direction you can offer would be appreciated.

 

[tjsox]

I had the P0174 code and check engine light running intermittently 2 years ago. It turned out to be a faulty purge valve. Dealer replaced it and problem solved.

 

[Snowbelt Spyder]

Andrea. Welcome aboard. Heat in the engine area is the V-Twin engine’s worst enemy. So, anything rubber is suspect, including the throttle body boot and plug wires. So first, changing those two little vacuum hoses is so easy to do, and works 90% of the time. And yeah, they always look ok until you take them off and flex them. Then the cracks appear visible. Plus, any vacuum leakage in those hoses can affect the signal from that sensor. While he is working in that area, have the dealer inspect the rubber boot that the throttle bodies mount in for cracks and that the clamps are tight. Consider replacing spark plug wires if they’re original. It’s well known on here that BRP wires on the V-Twin are junk. Site sponsor BajaRon can fix you up with the good stuff if you can get it installed. Sorry that your dealer is so mystified by all of this.