P0101: Mass or Volume Air Flow Circuit Range/Performance
The measured airflow does not agree with the engine computer's expected value.
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OBD-II trouble-code guides
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P0102: Mass or Volume Air Flow Circuit Low Input
The airflow-sensor signal is lower than the engine computer expects for the operating conditions.
P0113: Intake Air Temperature Sensor Circuit High
The intake-air-temperature signal commonly indicates an open circuit or an extremely cold reading.
P0117: Engine Coolant Temperature Sensor Circuit Low Input
The coolant-temperature signal voltage is lower than expected, often representing an implausibly hot reading.
P0128: Coolant Thermostat Below Regulating Temperature
The engine is taking longer than expected to reach normal operating temperature.
P0133: Oxygen Sensor Circuit Slow Response — Bank 1 Sensor 1
The upstream oxygen sensor is responding more slowly than expected.
P0171: System Too Lean — Bank 1
The engine computer is adding excessive fuel to compensate for a lean mixture.
P0172: System Too Rich — Bank 1
The engine computer is removing excessive fuel because the mixture appears rich.
P0300: Random or Multiple-Cylinder Misfire Detected
Combustion failures have been detected on multiple or changing cylinders.
P0301: Cylinder 1 Misfire Detected
Repeated combustion failures have been detected on cylinder 1.
P0302: Cylinder 2 Misfire Detected
Repeated combustion failures have been detected on cylinder 2.
P0303: Cylinder 3 Misfire Detected
Repeated combustion failures have been detected on cylinder 3.
P0325: Knock Sensor 1 Circuit Malfunction
The engine computer cannot reliably read the bank 1 knock-sensor circuit.
P0335: Crankshaft Position Sensor A Circuit
The crankshaft-position signal needed for ignition and fuel timing is missing or unreliable.
P0401: Exhaust Gas Recirculation Flow Insufficient
The expected response was not detected when EGR flow was commanded.
P0420: Catalyst System Efficiency Below Threshold — Bank 1
The bank 1 catalyst shows less oxygen-storage performance than expected.
P0430: Catalyst System Efficiency Below Threshold — Bank 2
The bank 2 catalyst shows less oxygen-storage performance than expected.
P0442: EVAP System Leak Detected — Small Leak
The sealed fuel-vapor system is losing pressure through a relatively small leak.
P0455: EVAP System Leak Detected — Large Leak
The fuel-vapor system cannot hold pressure because of a large opening or leak.
P0456: EVAP System Leak Detected — Very Small Leak
The fuel-vapor system has detected a very small loss of sealing integrity.
P0500: Vehicle Speed Sensor Malfunction
A valid vehicle-speed signal is not reaching the engine or transmission computer.
P0700: Transmission Control System Malfunction
The transmission controller has stored one or more separate fault codes.
P2096: Post Catalyst Fuel Trim System Too Lean — Bank 1
A lean indication has been detected after the bank 1 catalytic converter.
P11A0: Nissan Variable Compression Ratio (VCR) Control System Fault
On applicable Nissan vehicles, including the 2020 Altima 2.0L VC-Turbo, this manufacturer-specific code concerns the variable-compression-ratio control system. Confirm the exact Nissan service definition before testing or replacing components.