On the 2007 Nissan Sentra, the P2A00 is a fairly straight forward code pointing to a problem with the A/F Sensor (very similar in design and function to an oxygen sensor… just “smarter”). The sensor is mounted to the exhaust manifold. Carefully inspect the electrical connector and wire harness for any loose, broken or damaged wires. Make sure there are no leaks in the exhaust system, like in a pipe or at the manifold itself. If any leaks are found, these must be repaired first. If no problems are found, replacing the A/F Sensor should solve the problem. To replace, unplug the electrical connector and unscrew the sensor from the manifold.
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