# 2007 Nissan Sentra SES Codes



## cdbonds2001 (Feb 20, 2016)

I recently received the following code because of SES light: P0420.

I replaced the following part(s): NGK 24450, DENSO 234-9070 and Walker 53769.

The code cleared but 2 new codes appeared: P0137 and P0037.

What could be the cause of these codes? Also, what part(s) would I need to replace?

Any assistance would be much appreciated.


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## rogoman (Dec 16, 2004)

Both codes P0037 and P0137 point to a problem with O2 sensor #2 that's below the pre-cat.

Here are some possibilities:
* - Harness or connectors loose.
* - Heated oxygen sensor 2 circuit open or shorted.
* - Fuel pressure incorrect.
* - One or more fuel injectors may have a problem.
* - Intake system vacuum leaks.
* - O2 sensor defective.
* - Bad grounds.


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