Engine light when throttle let off

Tenereflyer

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New member here. 30 year old in Wisconsin. Bought a 2015 ES with 6500 miles this spring. Love the bike and up to 8800 miles now. I've recently noticed on hard deceleration (hard acceleration on freeway passing to 80 then dumping throttle back to mid 70's) the engine light will come on. Light will extinguish after a second or two. Anyone else experience this? Thinking maybe the hard decel is too much for the ECU to compute. Doesn't affect performance at all. Just curious if anyone else experiences this?
 

MFP

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New member here. 30 year old in Wisconsin. Bought a 2015 ES with 6500 miles this spring. Love the bike and up to 8800 miles now. I've recently noticed on hard deceleration (hard acceleration on freeway passing to 80 then dumping throttle back to mid 70's) the engine light will come on. Light will extinguish after a second or two. Anyone else experience this? Thinking maybe the hard decel is too much for the ECU to compute. Doesn't affect performance at all. Just curious if anyone else experiences this?
Are you sure that it is the engine light and not the oil light?
 

Sierra1

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Welcome from Texas. Didn't anybody tell you that this an old man's bike? That's not what I would consider hard accel, or decell for the Tenere. It's definitely not right though. And, if Eric can't answer the why, -TABASCO- will be able to.
 

Tenereflyer

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Thanks Sierra, people did always call me a old soul, whatever that means. And the price difference between this hardly broke in S10 and a new Twin was enough to persuade me. Throttle accel and the throttle decel Is probably more then 80mph to 70mph but that was the best way I could explain it.
 
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Jlq1969

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If the check light turns on, even if it is erratic, or for a short period of time, there is a fault… .and if there is a fault… there is an error/fault code saved. It begins by checking the fault codes stored in memory, but due to the type of fault you describe and at the moment it does, it is likely that it is "bothering" the pressure / vacuum sensor of the filter box, or vaccun lines as said WJ
 

EricV

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Welcome to the forum. There are lots of knowledgeable people here to help out. MFP is right, :D please add your location to your profile, (city/state is fine), it gives context to your posts and helps others give you better answers down the road since there are differences between US, Canada and EU bikes, plus California stuff thrown in. That way no one will need to ask in the future.

I haven't experienced this myself. My first thought is to check the battery connections and make sure they are tight. It sounds like the physical shift from accel to decel is causing an intermittent CEL, which limits the problem to wiring, at first blush. @Jlq1969 - brings up a great point and it's worth checking for codes. That might narrow the focus of the search if it's not a simple battery connection. A wonky fuse that is briefly disconnecting internally could also do this and the code might point to which fuses to check. My thinking is electrical Vs vacuum/pressure mainly because vacuum/pressure changes are softer and those systems are usually more tolerant of short spikes. Air compresses, after all. Whereas electrical connections, severed, no matter how briefly, display immediately and go away just as fast when reconnection occurs. It's probably something simple. These bikes are not prone to gremlins.

@~TABASCO~ is our resident mechanic that has more wrenching hours on the Super Tenere than most and has had the benefits of many customers bringing things to him for repair. He's seen more oddness than any of us riders having only had one or three S10s.

Good luck with the search to eliminate the flashing CEL and let us all know what you find so others can benefit from what you learn.
 

~TABASCO~

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Hello, like EricV and maybe a few others have mentioned I would first check the battery terminals. I’ve seen a TON of nonsense on the + battery terminal. Eye ball that out real good.
Second- is the bike showing any codes? If so will you post them?
Thanks
 

WJBertrand

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Since we’re talking about battery cables, don’t forget to check the cables at the starter solenoid end just above the battery. I’ve seen a couple reports of folks finding these loose.


Sent from my iPhone using Tapatalk Pro
 

Tenereflyer

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Well I pulled the bike into the shop before I left work this afternoon. Cleaned and tightened all connections/terminals. Fuses are all clean and no corrosion. Rode home and still have the same problem. Did some more troubleshooting on my way home. Definitely seems to be engine/RPM related as opposed to deceleration. Activated the ABS a few times from different speeds and light stayed extinguished. 4200RPM and above seem to be where the issue occurs. If I'm at 4200 or above and let go of the throttle the engine light will come on until down to about 3500RPM. Not showing any codes that I can see unless they are on a hidden page somewhere. Thinking maybe vacuum lines or TB sync?
 

EricV

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Engine codes are only displayed when you get into the diagnostic system on the bike. Here is a link to the process - LINK That should work on pre-2017 bikes. IIRC, those instructions are for the GEN II. Gen I are similar.
 

Tenereflyer

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Thanks Eric, figured that out just after my last post. Diagnostics was originally showing 4 codes in the history. 14, 19, 30, 70. I cleared them all and rode down the road, purposefully making the engine light come on (over 4200rpm and cut throttle). Only code now is 14. APS hose looks good and not dry rotted but I will replace it anyways. Just past my 8000mi maintenance check so I pulled the tank to do the service and get to know the bike better. The previous owner put a K&N filter in, think that may be the culprit? Not sure other people's feelings on them but I've never been a fan, at least of machines with MAP/APS. My multimeter is at work so I can't test the air pressure sensor tonight.
My mistake, was looking at the case breather line. Previous owner installed T fittings and lines to balance the fuel servos. The line going to the intake psi sensor was about ready to fall off. I'll replace all the lines and do the 8,000mi check and report back with the findings. Thanks for all the help guys, good group of help and people here. Even if you are all 30 years older than me ;)
 
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EricV

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Good job on getting the codes and clearing them so you could find the current code. They come back fast if they are still present.

I'm not a fan of the K&N filters either. I don't think that would cause the CEL though. The T fitting on the left line for Throttle Body balancing is common. No issue if the rubber is good and it's capped off. The OEM rubber caps do tend to crack over time. That line to the intake psi sensor may be the culprit. The breather line on the bottom of the air box is a pain to get back on. Long needle nose pliers work well. I have some long hose clamp pliers for that myself.
 

gapmtn1

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The breather line on the bottom of the air box is a pain to get back on. Long needle nose pliers work well. I have some long hose clamp pliers for that myself.
@Tenereflyer I have long 90 degree pliers like these that really help for such.
 

Squibb

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I'm thinking intake pressure sensor faulty/disconnected or throttle parameters out of sync.

Anyone got the detail, from the service manual, on resetting the throttle? I'm sure we had it on here somewhere - should be straightforward on an early Gen2 (pre-OBD).
 

regder

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My '15 had a bad intake pressure sensor, but I think was throwing code #13. You have a PM :)
 
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