Error P0051 on Infiniti cars

The P0051 code on Infiniti vehicles refers to a problem with the oxygen (O2) sensor heater control circuit. This code indicates that the Engine Control Module (ECM) has detected low voltage in the oxygen sensor heater circuit.

In terms of location, P0051 refers to Sensor 1 in Bank 2. "Bank 2" refers to the side of the engine that does not contain cylinder 1, while "Sensor 1" refers to the oxygen sensor that is located before the catalytic converter.

This is considered a critical issue because incorrect readings result in improper fuel management, which can increase fuel economy and emissions.

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• Infiniti DTC — Diagnostic Trouble Code (OBD II)

• The Check Engine light comes on.
• Fuel is not used economically
• Exhaust emissions increase.
• The engine may run rough, especially at idle.

The P0051 code can be caused by a variety of issues, including:

• faulty O2 sensor.
• shorted, open, or corroded wire in the O2 sensor heater circuit.
• blown O2 sensor heater element fuse.
• problem with the ECM itself, although this is relatively rare.

• Decreased Fuel Economy: The Engine Control Module (ECM) will switch to a richer fuel map, resulting in increased fuel economy.
• Decreased Engine Performance: A faulty oxygen sensor will cause hesitation, difficulty accelerating, and even intermittent stalling.
• Increased Emissions: Incorrect reading of the oxygen content in the exhaust will result in increased emissions of pollutants.
• Check Engine Light: P0051 will cause the Check Engine light to come on in your instrument cluster. This will limit your vehicle's functions to prevent further damage to the engine or other components.

The diagnostic process involves using an OBD-II scanner to read stored codes, then visually inspecting the oxygen sensor and associated wiring for obvious signs of damage. It may also be necessary to use a digital multimeter to check for voltage in the O2 sensor heater circuit.

The solution to this problem often involves replacing the oxygen sensor if it is found to be faulty. If the wiring is damaged, it will need to be repaired or replaced. In some cases, a blown fuse will need to be replaced. However, if the ECM is found to be faulty, it may need to be replaced or reprogrammed, which should be done by a professional mechanic.