o2 question for my 97

[derrick79]

the check engine light came on in my 97 5.7 vortec. and i scanned it and it said bank 1 sensor 1 low voltage. i checked the wiring and replaced the o2 sensor and my light is still on. anyone know for sure if the pcm needs to be reflashed after changing sensors? and roughly how much a dealer would charge for that?

thanks

[VileZambonie]

It doesn't need to be flashed you just need to clear the DTC. If you don't have a scanner or code reader for OBD2 just have autozone do it for free. Did you verify that was what you needed though? Make sure you have no vacuum leaks.

[derrick79]

yeah im pretty sure i have no vacuum leaks. it idles fine and there is no hesitation or miss when i accelerate. i was just ripping down the highway a few days ago and all of a sudden the light came on. of coarse i was in the middle of a trip so when i got to the city i borrowed a scanner and it said bank 1 sensor 1 low voltage. so since the truck was running fine i figured it was the sensor. but of coarse everything was closed seeing as it was easter weekend. so i came back and the truck drove fine for the 560km trip with no problems and to be honest i didn't really see a drop in fuel mileage all the much either. so all i need is that same obd scanner i used to erase that error code? appreciate the help

[Josh454]

If the code is in fact coming back check for power and ground at the sensor.  Oh and are you sure you replaced the correct sensor?

[derrick79]

yeah bank 1 sensor 1 is the drivers side before the cats. all wiring seems to be good. i dont have a multimeter so i cant actually check anything but looking at the wires they all look good, nothing is chafed or shorted anywhere.

[Blue 82]

Low voltage means she's runniing lean
Any exhaust leaks?

[derrick79]

no, not that i can tell.  the truck was running great i had no complaints, just got the front end done and out of no where this light comes on. and i am just stumped.

[VileZambonie]

Can you tell us what the specific DTC is? Example P0131

[derrick79]

well i decided to leave the battery disconnected overnight instead of just a few minutes and now my light is out. so i took it for a drive and my oil pressure and temperature was within operating range and the light hasn't come back on yet so i guess i will see what happens. but if i remember right it was P0131 error code that came up. did some research and it means that the voltage on that particular o2 circuit was low for more than 2 minutes. so like i said everything seems to be fine now, just have to play the waiting game and see.  thanks for all the help though guys.