What causes a P0171 and P0174 code?

Code P0171 indicates Bank 1 of the engine has a lean fuel mixture. P0174 indicates Bank 2 of the engine has a lean fuel mixture. P0171 is triggered by the engine bank 1 “upstream” oxygen sensor and P0174 is triggered by the engine bank 2 “upstream” oxygen sensor.

What causes P0171 and P0174 codes?

Code P0171 indicates Bank 1 of the engine has a lean fuel mixture. P0171 is triggered by the engine bank 1 “upstream” oxygen sensor and P0174 is triggered by the engine bank 2 “upstream” oxygen sensor. The oxygen sensor alerts your system when the condition is too lean meaning there’s too much oxygen in the exhaust.

What can cause P0171 and P0174?

Common Causes of P0171 and P0174

Vacuum Leaks. This is the most likely cause of too much air being taken into the system.
Mass Airflow Sensor (MAF)
Engine Computer Software Needs to Be Updated.
Fuel System Obstructions.
Intake Manifold Gasket Leaking.

What causes trouble code p0172?

A Thermostat stuck in the open position can mechanically cause a code P0172, especially in cold climates. The engine won’t warm up, preventing it from going into “closed loop” fuel control. Ignition misfires, like mechanical misfires, cause puffs of oxygen to keep hitting the Oxygen Sensors.

What does diagnostic code p0174 mean?

P0174 Diagnostic Theory for Shops and Technicians When a vehicle has the fault code P0174, it means that computer can no longer automatically adjust the mixture between air and fuel. Code P0174 applies to V engines as they will have two banks, Bank 1 and Bank 2.

What does the OBD code p0174 mean?

P0174 is an OBDII trouble code. The code technically stands for: Fuel Trim System Lean Bank 2 The code is thrown when the oxygen sensors detect that there’s not enough oxygen in the exhaust system.

What are error codes p0171?

P0171 is a diagnostic trouble code (DTC) for “System Too Lean (Bank 1)”.