Greg Bark

Hi, i had a bad o2 sensor and after i changed it the engine light went off. After about 2-3 hours the light came back on. so I took it to AutoZone to get the engine codes ( in the image). Now the check engine light comes on when I have approximately a quarter tank of gas , and when it is on I can't go over 3 RPM's. The car only has 85000 miles, any comments or suggestions will help. Thanks a lot!









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NoHope

Hello there

Did you reset your ECN? This particular model which i also own has this issue that the new o2 sensor is not recognized. Did you change both of the O2 sensors or just one?

Cheers

Greg Bark

I only changed one and im sorry but i dont know what ECN is?

NoHope

Hello
For best results, you gotta change both. ECU i spelled it wrong. Its the computer system of the car which is located underneath ur dashboard passenger seat. You can reset it by pulling the neg battery plug after you install your o2 sensors or get it reset at the local distributor autozone etc. Best bet is just unplug the battery fully for 15-20 minutes after your done with ur o2 sensor changing "BOTH". You wont have any issues after that.

Good luck

Greg Bark

Ok thanks , now does it matter if i already changed one (the one under the passenger seat) do i have to just change the other one or both?

NoHope

Hello
No problem. You gotta change both to new ones. Thats the only way, you cant change either maybe the other is good but still. You'll have again the same problem and keep waisting money. Just get them both changed and follow the intructions above and you're good to go.

Cheers

Greg Bark

Ok thanks i realy appreciate the advise. Sorry but one more thing, do u think theres anything wrong with the vtec solenoid? Because of the codes i was getting.

poorman212

Yes, you are going to have to solve the p2647. Simple question, what is the oil level and when was it last changed?

Greg Bark

I actually changed it a couple of days ago and i had about 3.5 quarts of the old oil

poorman212

Low oil levels or low oil pressure will trip the p2647 and cause the car to go into "limp" mode. Since you have changed the oil, clear the codes and drive it for a bit and see what/if any code(s) come back.

Greg Bark

I cleared them yesterday morning, by the end of the day it came back on. This morning while im going to work it turned off. I have a feeling it will come back on again

poorman212

Which code(s)came back. Both or just one?

Greg Bark

The vacume leak went away because i changed the air intake hose that was torn

Greg Bark

But the p2647 is is still there

tony_2018

high voltage circuit means something is amiss with the wiring.

Inspect the engine harness leading back to the ecu.

poorman212

If the oil level is good and the p2647 is back. I'd start testing the rocker arm oil switch/vtec oil switch

Greg Bark

Bought the switch yesterday gona install it today, is there any tips i should know to install correctly ?

Greg Bark

Just replaced the swith, the light is off hopefully it stays off. Honestly, thanks for the help I really appreciate it!!

poorman212

Hope it works out....I usually like to test things before replacing.

Greg Bark

Damn the light came back on and still can go over 3000 RPM

Greg Bark

Witch side would that be on? Would you know by any chance