With the Truck? So, I have been having an issue with my 02 sensors randomly and I am not sure why. Background is, about a week and a half ago, my CEL decides to come on with 3 codes, all based off the same code.... Primary code that keeps coming back is P0038 HO2S Heater Control Circuit High (Bank 1 Sensor 2) If memory serves me correctly I have seen the 4 versions of this, Bank 1 & 2 on Sensor 1 and 2... The only mod to the truck is flowmaster muffler, but that was installed over 2 years ago. No other "mods" have been performed or anything besides an Oil Change in the past Months. If the 02 sensor light just came on, and thats it, I would say "ok maybe its a bad sensor or wire or fuse" but the light keeps coming on and going off without rhyme or reason. I also thought it could have been gas, but I have gotten gas at Mobile, Sheetz, Shell, and Sunoco over the past 2 weeks and I have a hard time believing that all of those or more than 1 of them can cause the light to trip. Maybe i got bad gas in one, but a number of times? Anyone have any thoughts or ideas as to why this 02 sensor keeps tripping? I will probably check the fuse later on today after work, and I will probably just end up replacing the sensors as this is the second time this has happened where it goes on and off. The other time was over the winter.
I believe that's referring to the heater circuit. The O2 sensors have heaters so they don't foul. There is a separate circuit to control/power the sensor heater. So it's not the O2 readings it's complaining about. It's the heater circuit. So... bad sensors? If it's happening on both or all then it sounds more likely to be a connection. How are the harnesses connected to the PCM? Is there a single connector for all the sensors?
When you're under there, double check that the harness doesn't have any bare spots or broken wires too. If I remember correctly, a high sensor code usually refers to something not getting power. Like if you forgot to hook up the AIT after a motor job or something like that...:whistle:
I have no idea, I haven't had time to look into it in great depth. I have more time at the end of this week so i will most likely get a better look at things then. Most of the maintenance on my truck is done at a dealership and it was in for the 60,000 mile check back in March as the last major "work" done. I didn't notice anything doing the oil change but I wasn't looking either. I will go under there one of next few days and see if I can check the wiring and try to trace it back if I can. If I find anything unusual, I will see if I can get pics.
Check back side of all connectors to be sure the spades are all fully seated into it's pocket. If all connections and wires are good, and spades fully seated, change you sensors.
To add to my confusion, the light usually goes off after a fill up. Then back on at around 1/2 tank. I'd say this happens about 70% of the time. The other 30% it seems like its just random when its on vs off. I have some time today after work to get under and inspect the wiring and the connectors and such.
Wish I could help Steve. You've always been cool to me. But all I know is to check what the guys above said.
Thanks DooD I have the truck up on the ramps now. Letting it cool down a bit before I start reaching up into the hot exhaust areas and checking the wires. Just the first glance visual shows no obvious damage/meltage or anything out of the ordinary
Oh and rechecked the codes. Its the Heater Circuit on all 4 sensors. Any chance all 4 are bad? I doubt it, it sounds like it has to be a short or a fuse or something?
Do we remember who we are talking to here? LOL What should I be lookin for? I may end up taking it to the dealer and letting them have a look. There is only so much trouble shooting I can do lol
Ok, pull the PCM. When you do that and grab hold of it, check to see if it seems loose or anything (unlikely). Look really closely at all the contacts for any sign of corrosion. Re-seat the PCM and see if that did any good.
So the update is, after exhausting all efforts on my part, I took it to the dealer to check the PCM and make sure that it didnt need to be updated or anything. After confirming that everything was where it needed to be, it looks like its just time to replace the sensors. I still want to know why all 4 sensors (actually just the heater) would go bad on all 4 at one time?. Anyway, thats next on my to do list.
