Q: 2003 camry ac circuit needs replacement

Hi There, Depending on what your mechanic was referring to with respect to the AC system, there are a number of possibilities that may cause problems within the A/C system. Several components make up the entire "A/C circuit."

The locking issue you describe may be related to a faulty door lock mechanism. This is often related to a malfunctioning door lock actuator, a blown fuse or a faulty power door lock switch. When you use the door lock switch in the car it sends a signal to a relay which then activates an actuator inside the door. The actuator is the final step in the process in that it is a small motor with a set of gears that actually locks and unlocks the latch mechanism inside the door allowing the door to open. When this motor is bad, the latch mechanism will fail to operate and cause the door not to unlock as it is designed to. In the case of a bad door lock relay, the power, normally needed to send the signal from the switch when you activate it to the actuator motor is not there. This means the relay is not allowing the circuit to be completed and the actuator motor is not activated.

The check engine light related to the catalytic converter may be related to the catalytic converter being clogged or possibly to an oxygen sensor that may not be properly reading the exhaust gases coming form the catalytic converter. I would suggest having a professional from YourMechanic come to your location to properly diagnose and repair your vehicle.