Lexmex

It can only be the O2 sensor on that code. I would replace it.

praxis

thanks,
only one more question. the lead end that goes up into the underside of the vehicle body. i assume there must be a grommet that must be dismanteled so i can gain access to the connector end as it just goes right into the vehicle body. all i see is a black rubber sheath. it is easy to see how to dissconnect the sensor at the pipe side. does anyone have any explicit instructions for the other side so i dont screw something up, or break something off while trying to figure it out?

ive not seen any info much on changing this sensor. is it due to me being a dummy, or that sensor not being faulty much? also , must i use oem part.

Lexmex

For that you are going to have to look under the driver's side seat to get at that piece of the connector. I think some here have been able to get at it without removing the seat.

knk112

P0174
P0330
P1150

As I stated the VSC and engine light came on after the fuel injector cleaner was put in the gas tank. My car won't shift gears through its progressive cycle. I can only drive at 40 MPH without it shifting correctly (RPM rises above 4,000 RPM at 50) Please help!!!

Lexmex

Well, P0174 is an accompanying code. The P1150 is the A/F sensor (Bank 2, Sensor 1), one clearly visible in engine bay.

However, the nasty code that you have here and the reason you are getting the shifting problems is the P0330 which is Knock Sensor 2.

knk112

What steps should I take to fix it?

knk112

I found this on another posting:

you may want to run some fuel injection cleaner thru it also, along with cleaning the MAF again, all these codes indicate a lean mixture to me. too much air, not enough fuel, could be maf or fuel clogged up, also check/change the fuel filter if it's due..
(http://us.lexusownersclub.com/forums...hp/t23780.html)

Lexmex

Well, the knock sensor would definitey be the first (and I would have both replaced at the same time), but unless you are VERY mechanically inclined this is something for a professional mechanic to do and takes a considerable amount of effort to remove certain pieces and parts. I think we have had at least 2 or 3 who did it on their own, but certainly was not a walk in the park.

Fixing the knock sensor may clean up the A/F sensor error that you have and the accompanying P0174.

Lexmex

Well you can do this, and the only thing I have ever seen a fuel injector clear up is one of the A/F sensor codes. Happened to me in Mexico and I was able to clean it up using a Nology product called Powerboost.

However, I assume you have tried resetting the codes and still these codes pop up. The knock sensor is something that I don't think a fuel injector cleaner will magically fix, and everytime I have seen it occur on this forum, it has needed to be fixed.

knk112

Do you know how much the repairs will cost? How would you rate the severity on this? I'm very scared to drive the car right now. Don't think i can get this fixed for atleast another week.

Lexmex

You can still drive around on it, but you will be wasting more gas for sure. Repairs should be a few hundred dollars to do the knock sensor, but independent Lexus mechanics should be cheaper.

knk112

So this doesn't have nothing to do with the added Lucas fuel injector on the tank? do you have any idea what caused the the knock sensor? If I keep driving will it damage something else?

Lexmex

Knock sensors are just little microphones. They can go bad for any of a number of reasons, none of which you can really prevent. A common one we know of in Mexico is the use of lower octane gasoline than required, though this wouldn't happen as much at altitude where I live, but it did occur in more sea level areas.

You have the potential to damage something in the long run if left unchecked, but a week until you get it fixed won't hurt.

Thing I recommend right now is to make sure (cause it won't cost much) is to make sure you are running the highest octane and pull the battery cables off for a few minutes to reset the system. If you still get the light come back on, then the knock sensor should definitely be replaced should that same code come back up.

praxis

would running highest octane gasoline be recommended for the lexus rx300 to avoid problems. the manual indicates running premium gasoline.

Lexmex

Depends on the altitude. Lower octane is better in places about 2000 feet in elevation, meaning instead of 93 go 91, but I would have used the 87 octane in Mexico City if it weren't so high in sulfur. I generally would at least use a 91 octane, but nothing lower.