thank you. I *THINK* the conclusion is that both of the sensors don't start to get hot until the engine is running.

I have not specifically evaluated the cat, but it runs/drives/sounds/smells normal otherwise. Also, per the FSM, a bad cat is not a cause of this code. The computer opens the heater circuit when the engine is first started to get the O2 sensor 'hot" (How hot? not sure) as to help with sensor output. The code is for the heater circuit not behaving as it should, not an improper reading due to the gasses being off due to a bad/failing/no car converter. Again, per the FSM, it could be the computer, the sensor, or the wiring.

I'm thinking wiring now, but before I start tearing into the interior and wiring harness, the shop says they can see outputs in real time...I don't have the tools to do that. So I'm going to get their take on it.

It is the heater circuit causing the codes. Check the wiring near the sensors first, Toyotas don't generally have wiring problems inside the passenger compartment unless it's from mice. It's pretty easy to take the glove box out to get to the ECU to check the engine harness if you have to though.

In an off-topic car, I used a test light for this code once and chased the problem pretty quickly.

I tried to find the original article for you that was helpful for me when I learned that trick, and this article just popped up which is an excellent guide. He has smart suggestion to use your old harness for the light. Coincidentally, 3rd gen 4runner was one of the examples he provides and says that the 97 t4r could not use the light because there is voltage to both wires. I'm not familiar with the circuit, but he provides other approaches in the article. Definitely worth a read and just might help you out with where you are now.

Yea, I've had the glove box out and the ECU out a number of times now. Not that hard of a job. All the wiring connections at the ECM look fine.

Thanks. I've read that article before. It leaves us hanging. What was the remedy for the 4runner? I'm not seeing 12V on both of my heater wires, just one.

Again, i wouldn't think the wirng would be suspect, no work has been done on the car and all wiring at the ECM and at the sensor looks fine. I drove it for about 2 months and then the CEL popped on. Changed the sensor twice (correct denso part, tested with 12V dedicated and it gets hot quickly), had the computer repaired (not sure exactly what the repair was)....so I'm guessing wiring now.

We will see.

Got word from the shop, they are saying there is no continuity on the heater/ECM circuit, as some suspected.

I'm going to have them fix it, who knows where the wire break is. They said they could get the CEL off and pass inspection, which is what I need. I hope this settles it.

Thanks for all the input on my O2 sensor code. The shop said that both the 12V wire and the ECM sensor wire on the heater circuit were compromised, so they did an overlay and bypassed the broken circuit. They did not dig into the harness to find the broken area so I don't know what caused the cut wires, but the CEL is off now and has passed emissions testing.

Now on to maintenance and mods.

CEL is still off and all seems normal.

Just ordered ball joints and bolts from Camelback Toyota.
Ordered timing belt kit from ebay, along with new crank bolt.
Purchased new napa CVs

Gonna be a busy next few weeks.

In the middle of replacing both LBJs and going to attempt to reboot the passenger side inner CV.

Used a prybar to hold the hub while loosening the 36mm nut.

The LBJs were a bit worn, but still felt tight. I'm assuming they are original at 226k miles.

Does anyone know (or have) what the thread is on the castle nut that threads on to the steering arm? Mine are crusty and a bit suspect and I'd like to replace them.

Thanks

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Rebooted the passenger side inner CV with a napa kit. Holding so far.

Hit a milestone this morning...1500 miles in a year of ownership.

I've got the timing belt kit on the shelf, next in line.



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So had to reboot the driver side inner CV. Went with the Napa kit again.

Just got done with the timing belt and cam and crank seals. The belt was a no name and was cracked. Glad I did it. I really struggled with replacing the seals, they didn't appear to be leaking, but while in there....wish I had left them alone now.

So I put it all back together, drove it about 10 miles, and oil is pouring out around the crank seal. Super bummed. I used the seals with the aircabinman kit, and they went in straight. Anyone ever have this happen? I'm in the process of taking it all back apart now.



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So I took it all back apart, ordered 3 new OEM seals, installed them just as I did before, and now no leaks. Not sure what caused the oil leak, but it's been ok for about 1000 miles now.

And now it's for sale, picked up a FJ62 and the 4runner has to go, unfortunately.

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