Fault Code 14 Gen II - Solved

RossKean · Oct 29, 2016

Just starting to try to figure this out. I have had an intermittent issue with CEL coming on and showing a 14 fault code when the ignition key is cycled. Sometimes the bike is still running OK and other times I can only keep it going by holding the throttle open quite a bit and it runs horribly rich and dies instantly if I let off the throttle (especially when engine is cold). It is bad enough that I am afraid of getting stranded somewhere.

Note: Battery is fully charged and there are no symptoms that would relate to grounding issues. Also, I have not done anything under the tank in at least a month so it is not related to anything that has been done recently.

Fault code 14 says Intake Pressure Sensor (hose line); Intake air pressure sensor: hose system malfunction (clogged or detached hose). No idea whether this is related to a cause or a symptom.

Before I lift the tank and start doing stuff, has anyone run into this one before? Hope to be able to spend a little time on it tomorrow.

This thread may be interesting

Intake Air Pressure Sensor - Technical/Mechanical Problems - FJRForum

Still looking...

ionbeam · Oct 29, 2016

The referenced thread above is for a Gen I. Gen II lost one of the two pressure sensors so the FI calculations work a bit different.

It turns out that the Code 14 has shown up periodically. One mention is here along with the cure and another here.

RossKean · Oct 29, 2016

Thanks Alan

The thread I referenced is the same as the second one you mentioned and it was, in fact, for a 2008 Gen II.

In my searches, I did not encounter the first thread. Cause/fix seem similar in each case (gunk in line) so that it where I think I will start. Certainly before random part swapping.

I see you finally have a new avatar! (You were blank for awhile)

JamesK · Oct 29, 2016

I would also confirm that the Throttle Position Sensor is working per specs in the FSM while you're at it.

And yes, confirm that all the vacuum lines are clear of obstructions.

RossKean · Oct 29, 2016

JamesK said:
I would also confirm that the Throttle Position Sensor is working per specs in the FSM while you're at it.And yes, confirm that all the vacuum lines are clear of obstructions.

I did check out the TPS range as per the diagnostic screen and FSM instructions and it "appears" to be OK. TPS problems are hard to absolutely confirm via the diagnostic function but they are more likely to manifest themselves when the bike is hot. My malfunction seems to be worse when the bike is cold. (I don't think the TPS would have anything to do with a Fault Code 14.)

Tomorrow, I will clean out the hose that goes to the pressure sensor and the other vacuum hoses. Will hopefully find a "smoking gun".

Fred W · Oct 30, 2016

Just a thought. I've never had to troubleshoot one before, but if you have a MityVac (or similar) you should be able to exercise the pressure sensor while observing the results on the diag screens.

RossKean · Oct 30, 2016

Careful testing with a MityVac could be done if you knew what output voltage would result for a specific applied vacuum. The FSM gives an output range of 3.75V to 4.25V but doesn't say at what pressures. Diag 03 can be used to see if the device is working or not but that test doesn't help if the failure is due to plugged lines rather than a failed sensor.

In the thread I referenced in my original post, ionbeam mentioned that the bike should be rideable even without the pressure sensor by reverting to stored settings (lookup table). Perhaps that is with NO signal rather than possibly a wrong signal - mine certainly wouldn't be rideable when it is acting up.

I have a little time available today to dig into it. Hope it's something simple (and cheap).

RossKean · Oct 30, 2016

I think this says it all - earwax from the pressure sensor hose. Taking it for a ride later to make sure there are no other issues. The line was completely blocked between the connector and the sensor. All the other related lines were clear.

ionbeam · Oct 30, 2016

Good find! A $0.00 fix, even better. It looks like this is another of the off beat problems which us Forumites have been able to find and document for the collective.

I don't know if this is common enough to become a normal maintenance check, but if you own a higher mileage Gen II and you are already there for some reason (valve check) it sure wouldn't hurt to pull off the hose and do a little cleaning.

The FJR ECU seems to handle errors like a disconnected sensor just fine, it's when the sensor is 'out of range' that it gets indigestion and misbehaves.

RossKean · Oct 30, 2016

ionbeam said:
I don't know if this is common enough to become a normal maintenance check, but if you own a higher mileage Gen II and you are already there for some reason (valve check) it sure wouldn't hurt to pull off the hose and do a little cleaning.

The interesting thing is that it was only in the line between the sensor and the fitting that connects it to all of the vacuum lines. I'm wondering if it is some sort of assembly lube that was used and just took a million or so heat cycles to get it to agglomerate sufficiently to fully block the line (mine took almost 10 years and 163,000 miles). The stuff is quite gooey and probably softens up when heated. For anyone with a GenII who is doing stuff under the tank anyway (valve check, TBS etc) it wouldn't hurt to pop the line off the sensor and the connector end and run a pipe cleaner or something through it. A spritz with brake cleaner and dry with compressed air and its one more thing you probably won't have to be worried about again. Might take 5 minutes to do the one section or maybe an hour to remove the sensor and the network of hoses and connectors, clean them all and reassemble. (Not including lifting the tank and exposing the innards.)

ionbeam · Oct 30, 2016

RossKean said:
...it wouldn't hurt to pop the line off the sensor and the connector end and run a pipe cleaner or something through it. A spritz with brake cleaner and dry with compressed air...

Just don't spritz, blow compressed air or pipe clean the sensor itself. Nothing should go into the sensor's ~~orfice~~ opening, it is a sensitive electronic device.

The FSM says:

...the intake air pressure is introduced into the sensor unit, which contains a vacuum chamber on one side of thesilicon diaphragm, the silicon chip that is mounted on the silicon diaphragm converts the intake air

pressure into electrical signals. Then, an integrated circuit (IC) amplifies and adjusts the signals and

makes temperature compensations, in order to generate electrical signals that are proportionate to

the pressure...

RossKean · Oct 30, 2016

Good point! It could be a $200+ mistake. Yamaha is pretty proud of those little sensors.

I spritzed the hose and dried with compressed air. I did nothing to the sensor itself.

PhilJet09 · Oct 30, 2016

I'll add this to this winter's maintenance. Thanks.

Panman · Oct 30, 2016

Well at 96,000 I guess I had better figure out what lines your talking about.

RossKean · Oct 30, 2016

Panman said:
Well at 96,000 I guess I had better figure out what lines your talking about.

There are four short rubber hoses that come off four ports near the TBS ports. These are interconnected with plastic unions and there is a joined hose that goes to the back of the pressure sensor. The pressure sensor also has an electrical coupling. All the goo was in the piece joining to the sensor. Part #17 (5JW-82380-00-00) is the sensor in https://www.yamahasportsplaza.com/oemparts/a/yam/50045b54f8700209bc794087/intake-2 Part #12 is the hose that plugged.

Panman · Oct 30, 2016

Thank you sir, that is twice today I have learned something or found something useful.

RossKean · Oct 31, 2016

Quick followup - Between yesterday and today, I have done around 100 miles without a stumble or check engine light. It's an easy thing to disassemble and clean when you are under the tank. Based upon where it appeared and the fact that all of the lines from the ports were clean, I would suggest that the goo was there from the time the bike was manufactured (assembly grease??). Clean it once and you're done with it.

(I am assuming that this stuff did not originate inside the pressure sensor - can't imagine why it would be there on purpose)

Donal · Nov 1, 2016

RossKean said:
Quick followup - Between yesterday and today, I have done around 100 miles without a stumble or check engine light. It's an easy thing to disassemble and clean when you are under the tank. Based upon where it appeared and the fact that all of the lines from the ports were clean, I would suggest that the goo was there from the time the bike was manufactured (assembly grease??). Clean it once and you're done with it.
(I am assuming that this stuff did not originate inside the pressure sensor - can't imagine why it would be there on purpose)

Is there a possibility that it originates in the throttle body?

When the bodies are hot, the fuel will be vapourised, migrate up the tubes and then (additives) condense in the final bit of tube close to the sensor. Over time this could build up and cause the problem you are seeing.

Either way sounds like another (occasional) maintenance item to add to the list.

Thank you for documenting it........

ionbeam · Nov 1, 2016

Donal said:
RossKean said:

...I would suggest that the goo was there from the time the bike was manufactured (assembly grease??)...(I am assuming that this stuff did not originate inside the pressure sensor - can't imagine why it would be there on purpose)

Click to expand...

Is there a possibility that it originates in the throttle body?

When the bodies are hot, the fuel will be vapourised, migrate up the tubes and then (additives) condense in the final bit of tube close to the sensor. Over time this could build up and cause the problem you are seeing.

Either way sounds like another (occasional) maintenance item to add to the list.

Thank you for documenting it........

+1, back streaming from the TB is very likely the cause. There is nothing in the sensor which would cause goo in the hose. It's unlikely that this would contribute anything to the issue, but, the movement of the diaphragm in the sensor *may* encourage fuel vapors to be pulled into the hose where it condense as Donal suggests.

Next time someone with a newer FJR has the tank up perhaps they can do a swab inspection and see if it's something from the factory or if it grows goo over time. I'm in the 'goo over time' camp.

Fault Code 14 Gen II - Solved

Help Support Yamaha FJR Motorcycle Forum:

Well-known member

2 FUN

Well-known member

Got to ride

Well-known member

1 Wheel Drive

Well-known member

Well-known member

2 FUN

Well-known member

2 FUN

Well-known member

Nondescript FJR Hierarchy Displayed

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

2 FUN

Similar threads

Join the conversation!

Join today and get all the highlights of this community direct to your inbox. It's FREE!