sorry mrcel3, no way to check unless you invest in a code reader.
as blake said, Autozone will read the code for free.
Code P1135 is Bank 1 Senor 1, the Lexus has a batch of O2 sensors that were used on the 2002 that had problems.
If the car is CPO, then is should be covered. If you bought from an non-Lexus dealer, see what their warranty is/was.
Either way, the O2 sensor (if that is the problem) can be had for less money online and is very easy to change if you have an O2 socket, also available at Autozne.
Another word to the wise, use only Toyota/Lexus OEM O2 sensors.
Psot whatever code Autozone give you, we can tell you what the interp is.
good luck,
steviej