P0133 - Oxygen Sensor Circuit Slow Response (Bank 1 Sensor 1)
P1519 - Malfunction In IAC Valve Circuit
Diagnostic fault codes never say to replace parts or that they're bad. They only indicate the circuit or system that needs further diagnosis. The code 1519 is a perfect example. It doesn't specify what the problem is, just that that's the circuit that has the problem. The Engine Computer controls idle speed by adjusting the amount of fuel spraying from the injectors and the amount of air going through the idle air control valve. A problem with the IAC valve could allow in more air than desired resulting in an excessively lean mixture or one that's too rich. If the passage is blocked by carbon not enough air will go in and the mixture will be rich. Oxygen sensors only detect unburned oxygen, not fuel, so they don't report a rich condition, but they normally switch between rich and lean a couple of times per second, and when they fail to go lean, that's when the computer assumes the mixture is rich.
Failing to go lean over an extended period of time could set the code 133. That would not be due to a defective oxygen sensor. It's simply reporting what it sees. I would have code 1519 diagnosed first. Your mechanic will erase the codes, then see if any come back.
Tuesday, June 18th, 2013 AT 9:51 AM