Shed

Hi everyone. About a week after being in a Lexus dealers shop I had both the VSC and check engine light come on at the same time on my 02 RX300 AWD. I had the code read and its P1155 only. I've read on the forum a whole bunch of information and it's fantastic, but it's also led me to be a little confused. I believe when you only get a P1155 it's probably the heater fuse for B2S1 and doesn't necessarily require the replacing of the sensor, is that right? Can someone point me to the exact link of steps I should be following to check if it is the fuse before I go spending the money on the sensor?

Also can the code and the VSC lights coming on at the same time be related? I think I read somewhere that the VSC could easily be a plug undone somewhere. I had a 5k service, timing belt and full brake service done at the Lexus dealer.

Appreciate any help.

Dadikins

Yes, the 1155 (and I believe the 1135) is the heater fuse.

I had one of those codes last year, and ended up replacing the sensor, because I got tired of seeing the CEL (and VSC), wanted to make sure that no other "legitimate" codes would be thrown, and I was due for state inspection the following month.

I forget which of the codes (1135 or 1155) I got, but it was the sensor that is easily accessible. Ordered a replacement DENSO, soaked the old sensor with Liquid Wrench overnight, then a co-worker of mine helped me change the sensor.

So to answer your question - it isn't an immediate need to change the sensor, but I would highly recommend you do so, if for no other reason, in case another more serious CEL condition arises, which you aren't aware of. (I scanned & reset my codes daily until I replaced the sensor, just to be sure that no new codes would be thrown).

code58

Shed, I tend to disagree with Dan D. P1155 does indeed point to B2S1 which is the front sensor toward the radiator. There may be a heater fuse but i am not personally aware of anyone being fortunate enough to only replace the fuse, if indeed there is one. The heater is a common thing to fail with enough miles. It heats up to over 1500 degrees whenever it comes on (hundreds of thousand of times in it's lifetime) It is easy to check. Just do a continuity check on the 2 black wires or an ohms check. They are the heater wires and if there is no continuity, there is no heater and the DTC P1155 will be set. It is not something that will damage the engine if you drive it that way. I DOES need to be changed, but it wouldn't damage the engine if it was never changed. It wouldn't pass a state inspection but that's all. The heater is there to bring it to "closed loop" quickly (like the choke on an older car "opening"). If you are going down a long hill or in extremely cold weather it will come on to keep it in "closed loop" but under ordinary conditions, it spends most of the time simply along for the ride, doing nothing. Easy to check but don't panic otherwise. I have had an adaquate amount of experience with these. Be greatful it's that one, not the rear one.
The VSC COULD be the hose on the back of the intake air cleaner box disconnected. This happens often in servicing and the mechanic often doesn't notice it. The VSC is kind of generic and will come on for a lot of different reasons.

Dadikins

By "fuse", I didn't mean a physical fuse - I meant the "heater element" within the sensor. Sorry for the confusion.