4Runner engine code for A/F Sensor

I read an engine code of P1135 for my 2001 Toyota 4Runner with 93,000 miles. The translation was an "Air/Fuel Sensor Heater Circuit Response (Bank 1 Sensor 1).

From a previous thread, I learned that I should check the voltage to the two black wires going to the O2 sensor before the cat. If it is 12V, then I need a new O2 sensor. I took are reading and got 9.67V. Should I still replace the O2 sensor, or is there another electrical problem?

 

Toyota has had a horrible problem with this.

96% of the time it's the sensor.

What type of meter did you take the reading with and was the engine running when you did it?

 

It sounds like you may have a battery/alternator problem. Try taking a voltage reading at the battery with the engine off. It should be at 12.6 volts. If it is anything too much less, I would start looking for a batt/alt. problem.

 

I tested the battery and it is 12.9V which is as expected. I just replaced it last May. I tested the voltage across the two black wires and it reads 9.8V with the key in the ON position with engine off. When the engine is cranked, it reads 10.5V. I took this reading with a digital pocket multi-tester. I got it at the local Advanced Auto Parts. I think the difference in the reading from yesterday was due to the fact that I had been listening to the radio with the engine off for a while.

 

Is there anyone else that might be able to give me a difinitive answer? I would rather not spend $200 on somehting that doesn't need to be replaced.

 

I would have to say it's the A/F sensor. It looks just like a O2, but it's not an O2. Toyota has had a problem with them for a long time, and once one goes dead, others are likely to follow.

It can only be the A/F or the ECM. I highly doubt your ECM is going out or else your car would not even run.

No one in here can say with a 100% it's anything, but from Toyotas history with this P1135 codes, it's almost certain that's the problem.

When you do get the new sensor, get a new gasket and hardware for it.

 

Thanks for the help. I'll let you know how it works out.

 

I replaced the pre cat O2 sensor yesterday afternoon. I drove it around for a few miles and then turned the car off and restarted it to see if the engine light would go out. It did! Finally I had it fixed!

Then later that night after driving another 20 miles, the light came back on. I double checked to make sure everything was hooked up and tightened down properly and it still stayed on. Had the codes read again. It now reads the same P1135 code and has now added a P0770 - Shift Solenoid E Malfunction.

A little more background. I had to have the transmission rebuilt in May of 06. It had 72k miles on it at the time and it now has 93k. I should not be having transmission problems, right? But I know that the P0770 code is for the transmission. The transmission guy that did the work was recommended to me and gave me a 12 month warranty but I am obviously beyond that point now.

Any thoughts?

 

Did you get a OEM A/F sensor? Hopefully you did not use Bosch, they are junk. Have autozone clear your codes and see how it goes from there.

Have Autozone do a quick alternator test now. A good charging system will put out over 13.4v with engine running.