RX330 P430 Error Code

Hi,

I have a 2004 RX330 that received the 90K "tune-up" just 200 miles ago. (tune-up included Timing belt, all fluids, water pump, transmission flush, spark plugs). I picked up the car and the check engine light came on along with the VSC and TRAC light. Took the car back in and was told the O2 sensor was bad. They replaced the O2 sensor. Now - 200 miles later, the lights are back on. Took the car back into the shop and am told the catalytic converters are starting to go. They say they are slighly out of tolerance, but still drivable.

I'm having issues believing that the "tune-up" didn't cause these issues.

What are your thoughts?

Thanks - Tracey