meo

Hi;
Have Lexus RX300 1999. I have only one code reading P1133. I replaced the A/F sensor Bank1 but it still read P1133 . What else could be the issue? Any help please?

carguy07

OE/Denso or aftermarket? The rear one in the manifold, correct?

meo

I replace a new A/F sensor purchase on ebay brand After Market. Yes, is the rear one firewall.

hypervish

Well there's your problem.

Denso OEM only!

JAB

Did you reset the code?

Warvet369

Quote;Warvet369; 114--just had a problem with the Air/Fuel Sensor on my 1999 LexusRx300 and had to replace p1153 which cost me for the part $176 plus labor,but,if you go on line you can find it for a lot less. there are some guys on club lexus that have done this kind of work and they can tell you how to do it if you are able.I do know that the A/F Senor looks and installs just like a spark plug with a pi tail to plugin.I did not know this before i joined Club Lexus Forum.

5cardad

This is quite a bit later, but I'm having the same issue. I had code P1133. replaced the firewall O2 sensor with a Denso twice. Took off Pos battery terminal and took out computer fuse. code came back within 15 miles of driving. What else could this be. Tailpipe has colorless gases, no smoke, engine runs smooth, no misses.

artbuc

carguy07

I think a cracked exhaust manifold can do this too.

5cardad

I used the correct Denso OEM both times. Didn't use Anti-cease. (I find there is not need to use that if you use liquid wrench after you warm the car for just 5 min, heats just the pipe, but not the part. It comes out without much force at all. prior to this method, massive torque was needed).

Notice my handle, I've changed O2's on several of my vehicles, but this is the first code that is giving me the same code for replacing the O2 with Denso OEM, twice. Must be something else setting it off. Any advice on what else it could be? BTW I've cleaned the Mass air flow sensor as well.

maxSteel

A/F Sensor Circuit Response Malfunction
DTC No.DTC Detecting Condition

• Open or short in A/F sensor circuit
• A/F sensor
• Air induction system
• Fuel pressure
• Injector
• Engine ECU

5cardad

Thanks Max, went all through the air induction, and wiring, so I'm thinking your top 3 are out. how do I trouble shoot the injectors? I noticed the oil refil lid was split badly, when I took this off while the engine was running, the sound changed, because of the extra air. could this be throwing off the O2 codes?

LLawrence

how did you check electrical values on the plug to the rear a/f sensor? I too have an P1133 and P 1135, swapped sensors and still the same.

carguy07

Because they're both B1S1 codes