Airedog

I had a CEL a couple months ago and brought it in for some of my students to diagnose (I teach at an alternative hight school with a Career and Tech component.) My downstream O2 sensor was bad and they replaced it.

On the way home i got another CEL and stopped by AutoZone to have it read. The report was the codes above.

P0136 - heated O2 sensor bank 1 sensor 2 circuit fault
and
P2238 -O2 sensor circuit low - bank 1 sensor.


Back to my kids to diagnose. I only had a short time and they could not pin down the bug in the line.

Anyone have a heads up to help narrow the search? I won't be able to drop the truck back off to them until after the holidays, but if I can help them narrow the search, I won't need to leave my ride for multiple days (the class is 1/2 the day, but that only allows them about 2 hours of live work each day.)

I sure don't want to pay a shop to chase down an electrical bug...at least here the labor is free.

Thanks in advance.

Ironmike4x4

The P2238 code seems to be a Toyota specific code so Alldata at work will not give me the flow chart. A quick google search and mostly I found to replace the AF sensor (in my terms B1 S1 O2 sensor.) Or the driver's side first O2 sensor.

Airedog

Thanks, I will pass that on. I figure it will be some lab time for a couple of kids, but I'll point them in this direction.

Ironmike4x4

You'd probably want them to learn that on their own but I realize you want it fixed soon. Best way to learn is pull your hair out until you figure out the problem. That's why I have short hair!

BigBallsMcFalls

did they replace it with the exact Toyota OEM sensor, or something aftermarket ?

Airedog

I will check with the instructor when classes resume. I assume it makes a difference.

Airedog

Dropped it off for the class today. They used a Bosch sensor with the correct plug for the replacement. The instructor said, they'll figure it out. I told him to try OEM if all else fails.

Airedog

Denso sensor in there now. Still throwing the code. Time for a Toyota Tech.

Airedog

The Tech at Fox Toyota, Auburn, NY said the sensor that was just installed was damaged. I asked, "How was it damaged?", he said, "You can't see it, it's something inside, maybe the porcelain was cracked." The receipt states found replaced sensor damaged from being installed at BOCES.

I asked what would be the next step if the sensor was replaced again, and the light came on. He said, chase the circuit. That was done earlier. He did not reveal what the next step would be.

$102 for that little nugget of wisdom.

They also said TB, water pump, cam and crank seals will be $748 if they do it. I thought I had heard tensioners recommended, I'll do a search for that. One of my former students will do it for me, if he can locate...what is it he needs, to pull the crank.

He's a good kid and I trust him. I'd rather give him the cash and have him buy the tool. He's got hydrogen enhanced combustion (his own setup, Lowes parts.) on his little Honda and has gone from mid-30s to 47 mpg. My truck is on his list for this.

I may go for a new sensor myself, put it in and have somebody clear the code.

What do you think the chance is the shop class installed a defective sensor?

I was not pleased with Fox Toyota's service manager.

BigBallsMcFalls

dude, spend some money (under 20 bucks) and get a login to techinfo.toyota.com and you can have
ALL the official manuals and step-by-step diagnostic checks for everything, directly from Toyota itself.

Airedog

Solved.

It was not a damaged O2sensor. When the sensor was installed there was a good amount of rust on the studs. When the kids tightened up the nuts the tightened the sensor against the rust, not the flat mating surface. Exhaust was leaking out at the sensor. The shop I took it to ran a die down the studs, cleaned off the mating surface and tightened everything up good. No more light.

Damn tech at Fox Toyota in Auburn was going to make me pay for a new sensor when that wasn't even the problem. Damaged sensor, my ass.