hi, i think (not 100% sure), that there is no camshaft sensor in Lexus, they use what is called Variable Valve timing sensor (VVT Sensor) instead. see attached for the location

 

 

There is 4 cam shaft sensors 1 for intake 1 for exhaust on each bank they are located on top of the valve covers. intake cam sensor is towards the front of the engine and the exhaust is between two ignition coils. Intake is normally read as camshaft "A" and exhaust as" B" and which ever bank has the fault. Normally these faults can come on due to low oil. Crank shaft position sensor is behind the alternator. If trouble shooting you can switch any of these sensors as they are the same and clear codes to see if the fault stays with the sensor you suspect is bad. Hope this helps