gonzo

Ok this started awhile back with a bad 02 sensor, bank 1 sensor 1. I replaced it with a Bosch not knowing about the problems with them. About 2 weeks down the road it started setting several codes. After looking on here I went and returned it and ordered a Denso 234-4162. It was fine for awhile then started setting p0135. Checked everything I could. I did find a broken ground cable from the back of the block to the firewall. I replaced that and check the others. All good. So I ended up replacing the Denso again. The p0135 is still coming back. So I went and got one from another 4runner with a known good 02. Even say's Toyota on it. The p0135 still keeps coming up. I tried going to the TTORA site with the manual's but the one's for my 96 say's document not found.
I was going to test the wires from the 02 Sensor but I have no idea where they run to test them for a break or something.
I have searched until my eye's are crossed, lol.
Thank you

TheDurk

The wires run to ground and to the ECM (engine control module) behind the glove box. Here is what my paper '99 FSM says to do:

If 9-14V is present, problem is inside ECM. If not present, it's in the wiring or sensor. In your case, assume the wiring. You might try contact cleaner on the onboard-side connector to the sensor.

On my '99, the HTAF terminal is in the top row, in the second group from the left of the five groups. It is the fourth from the left. I hope your '96 is the same, I really don't know.

gonzo

Thank you very much. I will try that as soon as I can.
Thank you