Unhappy With Rx300

[RX Owner]

I love Lexus as a manufacturer for their supposed reliability, but I am dissatisfied with my RX reliability and wondered if anyone has any advice or comments.

I had a GS300 and was very happy with it. We moved to a hilly area and I decided that we needed a four wheel drive, so I replaced the GS300 with the RX300 in 2011. The car I bought was a 2006 RX300 with 31,000 on the clock (full dealer service history) and I always take the cars to a main dealer for all servicing. Since buying this car (mileage now 65,000) I have had to replace the Alternator, The water pump, the oxygen sensor for the catalytic converter, and now the engine management light has come on again. The dealer said that if the oxygen sensor replacement did not work then the car needs new catalytic converters at about £2,000!! each of the other repairs has cost an average of £600 (excluding services).

I bought Lexus because of reliability and this car, despite being pristine, has put me right off Lexus. It has been one thing after another. Can anyone suggest anything else for the current fault and restore my faith in the brand. Should a car of this age need new Catalytic Converters?

[ChrisIS200SportTTE]

No I don't believe it should. I've been having 02 sensor issues with my IS300. Lexus also gave me the line of if the sensor replacement doesn't work you'll need a new cat.

My response was "bull****"

Do you have an OBD2 code scanner? I suggest you get one, read the code(s) on your car then post them here.

I read my own fault codes on my car before taking it to the dealer. The code I had was Po156 O2 sensor circuit malfunction sensor 2 bank 2

If the cat wasn't working properly then it would throw up it's own code. Can't remember the code now but it's specific to the CAT. I told the dealer my code was being thrown by either faulty wiring or a hole in the exhaust. They seemed surprised that I knew the code and what I was talking about etc and then said "yes that's possible" so now they're having the car back Monday and I bet they don't tell me I need a new CAT!

[Duncan Roberts]

You won't find any similar history of troubles here.

Maybe change the dealer not the cat?

[Boxbrownie]

O2 sensors seem to be a common failure on the RX but not usually at that mileage, more like 90K or more, but they are fairly easy to replace in fact the forward manifold sensor can be replaced in a few minutes.

I had a the cat sensor pop up on mine a while back and was expecting to have to replace the sensor but it was just the sensor to exhaust flange leaking air causing a misreading of the mixture, it just needed a good clean of the mating faces.

I think the alternator failure is just bad luck, I have not seen that t my knowledge in here before (assuming the dealer got that diagnosis correct as well?)

[Boxbrownie]

Another point might be that the alternator and water pump are driven by the FEAD belt, as both failed it could have been the fact that the belt had been adjusted far to tight causing bearing failure on both components......dealer again?

[Tyrosman]

I believe the RX models are quite reliable, but not invincible, as the many posts both here and in the USA have found.

In my case I have had a leaking steering pump. Never experienced this problem in any other vehicle I (or my family) have owned.

Other problems being a leaking rear axle propshaft seal followed by a passenger side heater servo failure and now the heater matrix fails to heat, just lukewarm airflow.

I agree in most other aspects it is a great car to own, quiet, comfortable, a useful all-rounder.

[Duncan Roberts]

At ten years of age, it is past its so-called 'design life' and so some failures are inevitable. All cars develop faults but if you have enjoyed trouble free driving for the first half of its life that is acceptable. If you buy second hand then you are into the second phase of its life.

[Boxbrownie]

At ten years of age, it is past its so-called 'design life' and so some failures are inevitable. All cars develop faults but if you have enjoyed trouble free driving for the first half of its life that is acceptable. If you buy second hand then you are into the second phase of its life.

Its only a 2006 vehicle with 65K on the clock, hardly ten years old or even near its "design life".............I used to work for a major manufacturer at thier R&E centre and design life of most components was way above 100,000 miles depending upon the costs of the model.

I still wonder if the FEAD belt was tightened too much earlier in its life and caused failure of the water pump and alternator, seems a coincindence that both connected components failed unusually early.

[DanD]

I would also try a different dealer if you can. If you can't get to a Lexus dealer, it may be worth considering taking the car to a Toyota dealer for a second opinion.