jacek55

Hello,

I got the P1135 code:

Address 10 (Engine): 1 Fault Found:
P1135 - Oxygen (Lambda) Sensor Heating; B1&B2 S2; Heating Circuit: Elect. Malfunction

I replaced both sensors (bank 1 and bank 2) with brand new ones but the code keeps reappearing. What else can be wrong? Do I need to replace the convertor?

Thanks
Jack

Baetke

P1135 is thrown when the heater current is over 8 amps or under .25 amps, indicating a heater circuit failure. Since you just replaced the sensor I would assume the heater is ok. Check the fuse and relay that provide power to the A/F sensor heaters. The fuse is labeled 25A AFR HTR and the relay is right next to it. They are both located in the big black fuse/relay box in the engine compartment right by the diagnostic connector.

Baetke

hypervish

Welcome to Club Lexus!

Did you use Denso sensors?

code58

Jack, that code is specific for Lexus B1S1 (rear sensor, by the firewall). It shouldn't point to anything else, period. Did you replace the sensors yourself or have it done? If you still have the sensors you should be able to test them easily with just a DVM set to continuity. The 2 black wires are the heater wires and direction shouldn't make any difference. As Hypervish asked, what brand were they replaced with. It is very important to use OEM sensors which are Denso. Many times people have found out the hard way that aftermarket manufacturers sometimes don't know how to make a sensor that works well in a Toyota/Lexus product. Shouldn't be that way, but it is, trust me.

jcruise

Hi all, I am new to this site. You people are sharing a ton of useful information. I have had a problem with my 99' Lexus RX 300. It has been flawless performer for the past 5 years. Recently, however, I got a check engine lite. The error code was P0171 which is the bank 1 fuel ratio sensor. I bought one, which I was assured is a direct replacement and I installed it. I had a real problem removing the old one. I had to use a 1/2" breaker bar to remove it. Obviously, the threads were damaged. I did what I could to get the new sensor in. I couldn't get it to seat all the way. I did use the copper anti-seize on the threads. I plugged the harness together. Filled the gas tank to 3/4 full and drove it. The fuel tank needs to be about 3/4 full for the computer to work on resetting itself. Check engine lite went out after about 40 min. of driving, however, when I visited my friends garage he wanted to put his analyzer on it and it read a pending code P1153 which is the bank 2 sensor which is not getting the proper counts.
It has been three days since I installed the replacement sensor, and the check engine lite came back on. I will be verifying the code on Monday, Dec, 22nd. On Monday my friend put a snap on analyzer on the vehicle and determined that it is actually a P1153 error code which is bank 2 issue. He mentioned that he has seen this happen on other Lexus vehicles. The dominant failure triggers first, once fixed the next fault triggers. In this case P1153, bank 2 air/fuel ratio sensor. I will be installing an OEM DENSO sensor when I get it on bank 2.

I wish I would have read all the threads regarding these sensors before I tried replacing it. I would have been aware of some precautions to take before I began removing the old bank 1 sensor. Right now it is working without any faults.

Replacing sensors:
1. - Put vehicle in a position to access the sensor(s).
2. - Let the sensors cool, do not work on hot pipes.
3. - Spray the sensor threads with plenty of Rust Blaster, WD40, or Rust Inhibitor
4. - Next day disconnect the negative terminal on the battery.
5. - Separate the connector.
a. Bank 1 fire wall side is just below the intake manifold and can be accessed from the top.
b. Bank 2 is on the radiator side and the connector is easily accessible below the air filter box.
6. - Use a 22 mm sensor socket. Some links have mentioned that they have used offset 7/8" box wrenches.
The sensor should not be that tight.
7. - On the new sensor put copper anti-seize on the threads of the sensor only. Do not get any of this lube on the sensor tip.
8. - Hand thread the sensor into position.
9. - Just snug the sensor with the box wrench, or sensor socket. Should not exceed 35 ft lbs. That is not much pressure. As stated in an earlier link. "It's not going anywhere."
10. - Now you can make the wiring connection by joining the male and female harness together. You will hear a click when it is seated properly.

This is what I got out of the various sites I visited on this topic. When I get the new sensor. I just hope things will go a bit more smoothly for me with the bank 2 sensor.

artbuc

Not correct, maybe just a typo? P0171 indicates a lean condition in Bank 1 but often shows when lean condition exists in both banks, eg with a faulty/dirty MAF sensor.