Q: Driving down the road, the transmission stop pulling. Has code p0720. What sensor needs changing?

In the future, please include the model of Nissan and the motor size. This way we can be more certain we are giving you an accurate answer.

The P0420 code has to do with the catalytic converter. It will either be the catalytic converter or the downstream oxygen sensor. Diagnosing this requires a scanner and a five gas analyzer. The scanner is used to monitor the oxygen sensor operation and the five gas analyzer checks the emissions coming from the tail pipe. The gases coming from the tail pipe are used to determin whether or not the catalytic converter is working or not.

The P0520 code indicates a problem with the EOP (oil pressure sensor) electrical circuits. Testing this requires a wiring diagram and a test light.

The P0720 code suggests the output shaft speed sensor has failed. Before you go and replace it though, I highly recommend inspecting the wiring harness for problems. Check the connector at the sensor and make sure there is continuity through all the circuits of the speed sensor. Unfortunately, I can’t tell you where the output shaft speed sensor is located because I don’t know which model Nissan you have. It will be different for all of them. I can say however that it will be on the transmission and it will monitor the speed of the shaft that connects the transmission to the drive line.

If you should require more assistance with this, I recommend the following inspection to help you out. Transmission speed sensor replacement

Good luck!