danigirl

peas!! (as in their toes)

headache

We did disconnect battery also, still no luck. I just dropped off with the dealer I purchased from, so will post again with the results, lets hope for something small and insignificant!!!!(and inexpensive). I did purchase an extended warranty to last 6 years, 100k (after the regular warranty expired), so hopefully whatever the issue is will be covered. Thanks for quick replies.

3 weeks ago, had oil change. 100 Miles later, check engine light on. Codes for MAF and temp switch. Replaced MAF with new OEM, temp switch (GP Sorensen) approx 20 miles later, light back on. P1133. Replaced sensor (behind firewall). Did not re-set codes, but light went out by itself after a few miles. Approx 20 miles later, light back on. P1133 again. Replaced both O2 (bank 1 and bank 2, sensor 1). re-set codes. approx 20 miles later, light back on, now reading P1133 and P1153. Checked hoses, all appear ok, no leaks. Pigtails good on all O2's that I have installed. Car fax shows no accidents. I have had car 1 year. Oil change every 3K, changed plugs after purchase. Put approx 14K miles since owned. Car is taken care of and has all preventative maint. It was after the oil change that problem started, but have been told that couldn't have caused any problems. The only other thing I did to the car the day before light came on was, replaced a bad fuse (15) that controls the power outlet in the back seat. I work in the after market enviroment and have access to the right parts and people, have everyone stumpled. Have been advised to take back to dealer..not a Lexus dealer, but high end car dealer-know owner well. I have heard nothing but good things about this car, but losing the love over the past 3 weeks due to this mystery... Any other recommendations are appreciated. I have been dis-heartened to read the issues around these expensive sensors and MAF everywhere....but felt if I replaced all (due to codes) that problem would be solved. Is there any other "weird" thing I am not getting??

Hi, I have posted a few times on several sites and get mixed replies. I have replaced both O2 sensors (or Air Fuel Sensors), 2 times with OEM sensors. Denso 89467-48011. ( have also replace MAF with OEM and temp switch and PCV--due to other codes.) The light came back on after 20ish miles both times. Codes read P1133 and P1153. I asked an expert who has told me there are 2 bank 1 sensors on the back of the firewall. I have 1999 RX 300. Question 1............How many sensors are on the back of the firewall. Question 2 ............Any suggestions on why I keep getting the same codes after I replaced the only 2 O2 sensors I can find on the car (and on literature I have found on the web showing where they are located) Your help is appreciated

its not the O2 sensor, its the air fuel sensor. ive replaced them, 2 nos and now its ok, in normal working condition. ← what was the part numbers and OEM of the Air Fuel sensors you replaced?

I just had an "expert" tell me that I replaced the wrong 2 O2 sensors. I replaced both 89467-48011, one just behind the radiator and one behind the firewall. Are there any more than that in the front??? I know there is one behind the cat--and that one is a diff part altogether. This issue is that I replaced both and the check engine light came back on and codes are P1133 and P1153...same 2 sensors. So taking it to the shop now as I have replaced both sensors 2 x and the MAF all with OEM parts and still have same error codes. Any help is appreciated.

NOW I'M STUMPED. I replaced both front sensors with Denso part number 89467-48011. Reset. After 20 miles check engine light back on and codes: P1133 and P1153. which says that both sensors need to be replaced. So far I have replaced the MAF, temp control sensor, and both sensors 2 x, and continue to get these codes. What possibly is wrong now? Has anyone ever had this before??? P1133 - Air/Fuel Ratio Sensor Circuit Response Malfunction. It might be the Air/Fuel Sensor located. One air/fuel sensor located at the exhaust manifold and one before the catalytic converter, both the same part and same function. Normally both sensor to be replace. The rear sensor (after the catalytic converter) is the O2 sensor. Its look like your air/fuel sensor malfunction. FYI..... I got P1155 - Air/Fuel Ratio Sensor Heater Circuit Malfunction, its look like the same parts mentioned (air/fuel sensor). Replaced, and the engine check lights no more. Hope that helps. ← thanks What is the difference in an Air/Fuel Ratio Sensor and an O2 sensor?? I replaced the front one first, light came back on. Talked to a Lexus 'expert" who said I replaced wrong one. Put O2 on the the back of the firewall and light still on, that is when I got the MAF code, replaced it with OEM part, and light on again, giving same code it gave originally. So am going to replace both O2 Sensors and see what happens. What is irritating is that it is only coding one trouble spot..not 2. ← The two Air/Fuel Sensor and O2 sensor both work differently. Yes, normally have to change both of the sensor. Hopefully can solve ur problem. Might helps u, go to.... http://www.boschusa.com/AutoParts/FAQs/OxygenSensors/ Q. What does an oxygen sensor do? A. The oxygen sensor sends a signal to the engine computer based on the amount of oxygen in the exhaust gas. This signal is used by the engine ECU to fine-tune the mixture to the optimum level for maximum catalyst efficiency and longevity. A worn-out oxygen sensor can cause excessive gasoline consumption, elevated exhaust emissions, accelerated catalytic converter damage failures and cause engine performance problems such as surging and hesitating. Q. Except for the connector assembly, aren't all oxygen sensors basically the same? A. NO. There are five fundamentally different types of oxygen sensors: unheated thimble, heated thimble, planar, wide-band and titania. Within each sensor type, sensors vary in the design of the ceramic element, heater element and protection tube design, all of which affect sensor operation. Q. Where are oxygen sensors located and do they have different purposes? A. Oxygen sensors have been standard equipment on almost all passenger cars and light trucks with gasoline engines since 1980-1981. Most vehicles built before the mid-90’s have one or two oxygen sensors (two were used on selected V6 and V8 engines starting in the late 1980s). Oxygen sensors are normally located in the exhaust system before the catalytic converter to measure exhaust emissions as they come from the engine combustion chambers. In 1996 with the federal mandated use of on-board-diagnostic systems (OBDII), vehicles also require additional oxygen sensors after the catalytic converter, to ensure that the converter is operating properly. ←

my experience has been when the car shakes at higher speed the tires are out of balance. cheap fix--balance and rotate. When you are braking, and the car shutters then you have issues with the rotors. Ceramic brake pads which are great for low brake dust, they do waste your rotors quicker than regular pads. Rotors work with your brakes, not acelleration.

there are 2 (same part) in the front before the catalyst and one behind (different part from the other 2) The 2 front ones are $189, the one on the back 100. #1Motormart.com So, a total of 3 sensors. ← thks for ur reply, u r right, the front two sensor actually air fuel sensor and the last sensor (below) O2 sensor. I've change both air/fuel sensor (before the catalyst). and no more engine check lights. thks ← What is the difference in an Air/fuel Sensor and an O2 sensor? Are they not the same thing???

P1133 - Air/Fuel Ratio Sensor Circuit Response Malfunction. It might be the Air/Fuel Sensor located. One air/fuel sensor located at the exhaust manifold and one before the catalytic converter, both the same part and same function. Normally both sensor to be replace. The rear sensor (after the catalytic converter) is the O2 sensor. Its look like your air/fuel sensor malfunction. FYI..... I got P1155 - Air/Fuel Ratio Sensor Heater Circuit Malfunction, its look like the same parts mentioned (air/fuel sensor). Replaced, and the engine check lights no more. Hope that helps. ← thanks What is the difference in an Air/Fuel Ratio Sensor and an O2 sensor?? I replaced the front one first, light came back on. Talked to a Lexus 'expert" who said I replaced wrong one. Put O2 on the the back of the firewall and light still on, that is when I got the MAF code, replaced it with OEM part, and light on again, giving same code it gave originally. So am going to replace both O2 Sensors and see what happens. What is irritating is that it is only coding one trouble spot..not 2.

thank you for the info. I work in the aftermarket arena. Bosch purchases their sensors from Denso and packages them in their Bosch box. I have been told this before when I owned my 4-Runner...same type issues with sensors from OEM only, however, you can look at the Bosch part and see the Denso name and part number on it?????

there are 2 (same part) in the front before the catalyst and one behind (different part from the other 2) The 2 front ones are $189, the one on the back 100. #1Motormart.com So, a total of 3 sensors.

I am a new RX300 owner purchaesed last July, curently at 61K and check engine light on. P1133, I changed the O2 sensor(behind firewall) w/ Bosch Part 13333, MAF coded, changed MAF with OEM part. Light back on again, P1133--which is same code of part I just changed. Any ideas?? Also, what is the difference in an A/F sensor and O2 Sensor? Are they the same thing or are they different parts? I am increasingly frustrated that I have replaced high dollar parts and continue to get same codes as if parts never changed.

code read P1133-I replaced O2 sensor behind firewall. light on again, replaced MAF with OEM part, light on again, giving same P1133 code...NOW what? Anyone have the same issue or can you help