For the record : P0125 & P1135

[Jack Deth]

i already fixed this on my '99 avalon, just posting for future reference.

the CEL came on. then the traction control shut itself off rather abruptly and would not go back on, leaving me with 2 amber lights glaring at me. toyota shuts off the traction control on purpose when you spin a wheel with a cel on. there isn't necessarily anything wrong with the traction control.

seems there is no more "counting the flashes" of the cel to get the code anymore, so i bought a simple code reader, an Actron CP9125, for $50. seems to work fine, but the meter itself doesn't display the meaning of the code, just the code itself. they give you a book and a cd for lookup, so it's nbd.
i got codes P0125 and P1135. the standard definition for P0125 is "insufficient coolant temp to enter closed loop control", but not for toyota. toyota's definition for this code is "fuel air metering fault". P1135 is a toyota code for "a/f sensor heater circuit malfunction bank 1 sensor 1".
this is the upstream sensor mounted in the exhaust manifold nearest the firewall. i removed the sensor from under the hood with some PB Blaster, a 22mm wrench and a 2' length of pipe. it wasn't that it was so tight, but without the pipe you can't get any force on the wrench because of where it is located. the toughest part was unlatching the electrical connector. i checked the sensor's heater with an ohmmeter across the two same-colored wires, it read open. while i was under the hood i looked at the emissions sticker on the firewall. it clearly stated it was a CA emissions car, even though i'm in CT.

i bought a Denso brand sensor from rock auto, P/N 2349007 air/fuel ratio sensor, right, calif. $113. it comes with anti-seize. fit exactly, cel off, traction control working.

[rockguitar]

I know this is an old thread, but it has good information. I just replaced the exact same sensor, with the exact same Denso OEM part. I didn't have a 22 mm wrench on hand, so I ended up at my auto parts store talking to a mechanic. I found a deep throat 22 mm socket and asked him if he thought it would work for the oxygen sensor (technically the air/fuel sensor). He suggested that the wires would get in the way of the socket and to check with the store to see if they had an oxygen sensor socket kit, it came with 3 sockets including the 22 mm socket. Lo and behold, they did and it was only a $29.99 deposit for the loaner. This was at "Advanced Auto Parts."

I'm glad I talked to him because getting the sensor off was easy after that. If you know the sensor is the problem, then I guess you could cut off the wires from the sensor to replace using a normal socket. Otherwise, the oxygen sensor socket kit would be worth it, if you want to reuse the sensor. It has a slot in the side to accomodate the wires. See the link for an example

Amazon

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