P10E4 Error Code Diagnosis?

[YukonXLMan]

Friends
In running my vehicle down from NE to FLA last weekend, I got a blinking check engine light. Initial diagnosis was P0300 (of which much has been written of in this forum). I believed it to be from poor gasoline. After using a few fuel additives and the highest octane fuel I could find on the way back, I no longer have a blinking check engine light, but I continue to get P0300 and P10E4 error codes each time I clear them, restart the engine, shut engine off and recheck for codes. The P10E4 error code reads "Ignition on/start circuit source bypass relay control performance."I look up the error code on autocodes.com and it recommends checking a valvetronic relay supply voltage. I must admit, I cannot find a fuse or relay on my 2017 Yukon XL that matches that name.

Any recommendations on how to begin debugging this?

 

[STORMIN08]

so i had to look that code up and sure enough...my 2017 tossed the same code on a trip from STL to Louisiana. a flashing indicator is a live right now issue, a solid light is usually a sensor issue.

i have noticed that from time to time, i get a slight spark knock under very light load at highway speeds. now, i have switched to 89 octane since our temps are getting warmer and have not had the issue.

remember, octane is number of knock avoidance, it is not necessary to increase engine timing to see performance gains of any kind (it is a very minimal increase in most pump gas cases when going for performance).

anyway, be attentive to weather conditions, and see if higher temps have any role....i have 58K on ours and i am planning on doing plugs and checking wires very soon.

 

[Tiredmechanic23]

https://www.autoserviceprofessional.com/articles/4413-wet-headlamp-causing-problems

Water in the headlamp and related wiring can cause that code.


Other things may cause it as well. The valvtronic junk is for BMW engines. On any other vehicle including GM its basically saying a accessory circuit that should be key on power is getting power when it should not be (bypassed). Could be water somewhere or a short or a relay. This one may take some chasing to find. Possibly either the wiring/circuit or the relay that control ECM startup is bad/flaky

any aftermarket accessory? Anything plugged into the OBD port?

 

[YukonXLMan]

Thank you for your replies. I'll chase the water issue starting with headlights and fog lights, as both have aftermarkets in them. I'm going to burn down the gas tank to the light, then fill again with premium and more gas treatment to see if I can make the other code go away. nothing plugged into ODB port. Keep those cards and ideas coming! Thanks!

Out of curiosity, does anything bad occur if I cannot trace a P10E4 down and simply leave it as is???

 

[dbaudo1]

I realize it's been almost a year on this but did you ever figure out what was causing the P10E4 Code? i'm having the same code on my '17 yukon but also having other issues like the gauge cluster going haywire and continuously restarting itself. also the vehicle is hard to start as well and the keyless entry seems to be delayed in performing the functions

 

[YukonXLMan]

Sadly, no. Still a mystery. Chose to leave as is with no further issue to date.