P155b-00 - Nissan

, as the exhaust manifold and oxygen sensors reach extremely high temperatures during operation. If you'd like to narrow this down, let me know: What is the year and model of your Nissan? (e.g., 2015 Altima, 2010 Frontier) Do you have access to a multimeter other codes appearing alongside this one (like P0300 or P0174)?

Use an OBD-II scanner to watch the O2 sensor voltage while the engine is running at operating temperature. It should cycle rapidly between approximately 0.1V and 0.9V. nissan p155b-00

: Nissan vehicles utilize a battery current sensor (often mounted directly on the negative battery terminal) to measure live charging and discharging. If this sensor fails or gets disconnected, it flags power management codes. Alternator / Charging System Issues , as the exhaust manifold and oxygen sensors

: In some cases, resetting the code is recommended to see if it was a "soft" failure before replacing expensive parts. Sensor Replacement Use an OBD-II scanner to watch the O2

Potential slight fluctuations in engine RPM if the alternator load switches erratically. JustAnswer Common Causes Defective Sensor

Using a multimeter: