Need To Confirm Code Before Replacing Sensor!

[drmull]

Hello -

My '99's CEL came on the other day. My wife drove it for a while before I could read the codes. It showed P0125 & P1155 with a few pending (P0171,P1150,P1153,P1155). I cleared them and drove the car myself. Took about 3 miles before the CEL came on again. I stopped & checked the codes - P0125 & P1150 (pending) - nothing else.

So...am I correct that this shows P0125 as the "real" problem? I was told the first code thrown is most genuine - that proved true on the 3 coil packs I've replaced!

What do you guys (and girls) think I should look for first? I'll check the coolant level but where is the coolant temp sensor (I read that's what P0125 could be).

Would P0125 & P1150 together point to an A/F sensor instead? I just want to fix the right thing & my wife has to drive the car out of town in a few days - she's on me to "fix it" before then...

Thanks very much for any help.

I've been poking around while waiting for a reply (hopefully). I see 1150 is B2S1 & 1155 is B1S1. I also read that the P1025 could be a false code caused by a bad sensor. Any truth to that?? How in the world will I know which sensor is the real problem?? Confusing...

[code58]

Hello -

My '99's CEL came on the other day. My wife drove it for a while before I could read the codes. It showed P0125 & P1155 with a few pending (P0171,P1150,P1153,P1155). I cleared them and drove the car myself. Took about 3 miles before the CEL came on again. I stopped & checked the codes - P0125 & P1150 (pending) - nothing else.

So...am I correct that this shows P0125 as the "real" problem? I was told the first code thrown is most genuine - that proved true on the 3 coil packs I've replaced!

What do you guys (and girls) think I should look for first? I'll check the coolant level but where is the coolant temp sensor (I read that's what P0125 could be).

Would P0125 & P1150 together point to an A/F sensor instead? I just want to fix the right thing & my wife has to drive the car out of town in a few days - she's on me to "fix it" before then...

Thanks very much for any help.

I've been poking around while waiting for a reply (hopefully). I see 1150 is B2S1 & 1155 is B1S1. I also read that the P1025 could be a false code caused by a bad sensor. Any truth to that?? How in the world will I know which sensor is the real problem?? Confusing...

Drmull- I hate to do this to you, but since no one has answered yet, and I am not sure what the solution is, I suggest you go to www.obd-codes.com There is a tremendous amount of information there. They have links to forums and I can guarantee you will find helpful information there, it just takes some digging sometimes. There is a Lexus specific page for the codes from P1100 to P 1780. Good Luck!

[drmull]

Thanks for the reply -

It seems, from what I can find, that the P0125 code is being thrown because of a bad A/F sensor. Since I've gotten 1155 & 1150 (pending) I have no idea which sensor is really the troublemaker. I've got no way to test the sensors, so it looks like I'll have to pay to have them checked...bummer. Good news - there's a Lexus shop that's cheaper than a dealer. Bad news - it's about 50 miles away.

I have to say (venting here) that the RX300 has begun to have too many gremlins IMO. Knock sensors went bad...replaced & then the OEM replacements were bad. Three of the coil packs have failed. I disconnected the sensor to the brake fluid reservoir because it failed and shows low fluid. The servo for the A/C mode has gone nuts. Lots of failed bulbs, etc. In contrast, my '93 Acura Legend is running strong without any failures of any kind. No CEL, all the original stuff works...I'm just sayin"! I do love driving the Lexus, though.