Urgent Help: 99 Rx300 With Cel {p0141, P0171, P1130 P1150}

[lahermano]

Hi Experts,

I am in desperate need of help with my lexus CEL problem.

1. GAS Mileage is very bad now

2. Autozone looked at it and OBD-II reported Error codes {P0141, p0171, p1130 P1150}

I am sure you guys have seen this problem.

My Questions are

1. what diagnosis can i infer from ? O2Sensor bad and need replacement ?

a. If replacement what brand should i choose and where to buy

b. Do i really need to get the Lexus part ? (Lexus at Grapevine quoted $204.95 for the part)

2. Could these be a different issue other than O2Sensor issue ?

All are the 4 error codes resulting to one problem or they are different problems that i have ?

3. Are there any pics of how to replace it ? I looked at the engine and there is a visible O2Sensor. Is that the only one to replace ?

4. They talk about Bank 1 Bank 2 etc. What are these and how to locate them ? and how many sensors are there that need to be looked at ?

All responses are greatly appreciated.

Thanks very much for the help.

[gordonw]

P1130 and P1150 refer to the two air fuel ratio sensors. Those are the front oxygen sensors, one in each manifold. P0141 refers to the heated/downstream oxygen sensor, next to the catalytic converter in the mid/center pipe. P0171 probably is refering to your mass air flow meter in the the engine air cleaner.

[blk_on_blk]

Some of these codes are probably 'chain reaction' codes, meaning they are getting triggered because some other component is not functioning properly, and then !Removed! up the system. P0171 is probably one of those codes, for it means 'lean bank one'. P0141 means the O2 sensor on bank 2 is slow to respond. The other codes are saying they have circuit malfunctions. All these codes refer to an air/fuel metering issue.

I would first try cleaning the MAF with automotive electrical spray cleaner and see if that helps your issue.

What would really help you is to get a code scanner. Then you can clear the codes, and as soon as the CEL trips on, you can pull the code right away. That way you can get the first code(s) that shows up, which is usually the problematic code... if you continue to drive the vehicle with the CEL on and an air/fuel issue, it almost always causes additional 'chain reaction' codes to show, and those can be misleading to the root problem.

Again, I would clean the MAF, then reset the ECU (I do it with my code reader, or you can disconnect the battery for a few moments, too). Then, when the first code pops up, scan for it. That'll point you in the right direction.

[lahermano]

Thanks V Much.

I will try that. Last month or so i got CEL then i cleaned the MAF sensor with the cleaner CEL went away. It came back.

will try again..

Some of these codes are probably 'chain reaction' codes, meaning they are getting triggered because some other component is not functioning properly, and then !Removed! up the system. P0171 is probably one of those codes, for it means 'lean bank one'. P0141 means the O2 sensor on bank 2 is slow to respond. The other codes are saying they have circuit malfunctions. All these codes refer to an air/fuel metering issue.

I would first try cleaning the MAF with automotive electrical spray cleaner and see if that helps your issue.

What would really help you is to get a code scanner. Then you can clear the codes, and as soon as the CEL trips on, you can pull the code right away. That way you can get the first code(s) that shows up, which is usually the problematic code... if you continue to drive the vehicle with the CEL on and an air/fuel issue, it almost always causes additional 'chain reaction' codes to show, and those can be misleading to the root problem.

Again, I would clean the MAF, then reset the ECU (I do it with my code reader, or you can disconnect the battery for a few moments, too). Then, when the first code pops up, scan for it. That'll point you in the right direction.

[lahermano]

Thanks V Much.

I will try that. Last month or so i got CEL then i cleaned the MAF sensor with the cleaner CEL went away. It came back.

will try again..

Some of these codes are probably 'chain reaction' codes, meaning they are getting triggered because some other component is not functioning properly, and then !Removed! up the system. P0171 is probably one of those codes, for it means 'lean bank one'. P0141 means the O2 sensor on bank 2 is slow to respond. The other codes are saying they have circuit malfunctions. All these codes refer to an air/fuel metering issue.

I would first try cleaning the MAF with automotive electrical spray cleaner and see if that helps your issue.

What would really help you is to get a code scanner. Then you can clear the codes, and as soon as the CEL trips on, you can pull the code right away. That way you can get the first code(s) that shows up, which is usually the problematic code... if you continue to drive the vehicle with the CEL on and an air/fuel issue, it almost always causes additional 'chain reaction' codes to show, and those can be misleading to the root problem.

Again, I would clean the MAF, then reset the ECU (I do it with my code reader, or you can disconnect the battery for a few moments, too). Then, when the first code pops up, scan for it. That'll point you in the right direction.

Thanks all for the responses

I had replaced the Oxygen Sensor and it did the trick. I had to remove the driver side seat to have access to the connector.

[lahermano]

For the Error codes P1130 P1150, I used the gumout from autozone and techron for 2 tanks of gas to clear those. The injection system probably had some clogging and the Air/Fuel ratio sensors weren't bad. Also i think as one pointed out, they were a cascade effect for p0141 oxygen sensor really being bad.

[giahamzui]

thank you all for the tips (i have the same problem)

:)

[lahermano]

All, Finally it turned out to be the Oxygen Sensor. the one with the flange.

I replaced it and all error codes were gone. I got back the good performance and expected mileage now.

Did not have to replace the Air/Fuel ratio sensors at all.

thank you all for the tips (i have the same problem)

:)

[iamhere9]

I've same issue with my 00 RX 300, How did you guys replace oxygen sensor ? Is there any step by step guide with pics, sorry I am a newbie.

Thanks

[lahermano]

I've same issue with my 00 RX 300, How did you guys replace oxygen sensor ? Is there any step by step guide with pics, sorry I am a newbie.

Thanks

Well, If you are pretty sure that the oxygen sensor went bad.

then it is very easy to replace that if u are a DIY guy.

Unfortunately i don't have a pics to show the step by step. but can tell how i did it.

1. i removed the driver seat 4 bolts and slid that seat back to have access to the oxygen sensor that is under the carpet off driver seat.

2. remove the 2 nuts that fit the oxygen sensor, located under carriage and in the exhaust pipe under the driver seat side.

3. Pry out the rubber tubing that goes to the driver seat. and not follow the same steps to replace the new Oxygen sensor.

It took me 1 1/2 hrs to do it.. If i do it again i probably would get it done in less than 30 mins.

pretty easy job... no need to go under the car or lift the car.

It is more difficult to replace the Air fuel ratio sensors than oxygen sensor.

[womacje]

Which bank was this sensor? is this bank 1 under the seat or was this another bank? i'm looking for bank 1 O2 sensor, where is that? thanks.

I've same issue with my 00 RX 300, How did you guys replace oxygen sensor ? Is there any step by step guide with pics, sorry I am a newbie.

Thanks

Well, If you are pretty sure that the oxygen sensor went bad.

then it is very easy to replace that if u are a DIY guy.

Unfortunately i don't have a pics to show the step by step. but can tell how i did it.

1. i removed the driver seat 4 bolts and slid that seat back to have access to the oxygen sensor that is under the carpet off driver seat.

2. remove the 2 nuts that fit the oxygen sensor, located under carriage and in the exhaust pipe under the driver seat side.

3. Pry out the rubber tubing that goes to the driver seat. and not follow the same steps to replace the new Oxygen sensor.

It took me 1 1/2 hrs to do it.. If i do it again i probably would get it done in less than 30 mins.

pretty easy job... no need to go under the car or lift the car.

It is more difficult to replace the Air fuel ratio sensors than oxygen sensor.