P2251 Mitsubishi Oxygen (O2) Sensor Negative Current Control Circuit / Open (Bank 1 – Sensor 1)
Possible causes
– Rear Air/Fuel Ratio Sensor Bank 1 Sensor 1 harness is open or shorted
– Rear Air/Fuel Ratio Sensor Bank 1 Sensor 1 circuit poor electrical connection
– Faulty Rear Air/Fuel Ratio Sensor Bank 1 Sensor 1
– Rear Air/Fuel Ratio Sensor Bank 1 Sensor 1 circuit poor electrical connection
– Faulty Rear Air/Fuel Ratio Sensor Bank 1 Sensor 1
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P2251 Mitsubishi Description
The rear air/fuel ratio (A/F) sensor (bank 1, sensor 1) is installed in the exhaust manifold and detects oxygen content in the exhaust gas. The rear A/F sensor transmits a signal to the powertrain control module (PCM), and it enables overall feedback control. The PCM controls fuel injection duration by comparing the target air/fuel ratio with the rear A/F sensor signal. When the VSB1 terminal voltage is more than a specified value for a predetermined time, the PCM detects a malfunction and stores a DTC.
Mitsubishi Vehicle:Mitsubishi Aspire,Mitsubishi Airtrek,Mitsubishi Adventure,Mitsubishi Galant,Mitsubishi Tredia,Mitsubishi Strada,Mitsubishi RVR,Mitsubishi Pajero,Mitsubishi Outlander,Mitsubishi Montero Sport,Mitsubishi Mirage,Mitsubishi Libero,Mitsubishi Legnum,Mitsubishi Lancer,Mitsubishi i Miev,Mitsubishi GTO,Mitsubishi FTO,Mitsubishi Eterna,Mitsubishi eK,Mitsubishi Eclipse,Mitsubishi Diamante,Mitsubishi Delica,Mitsubishi Cordia,Mitsubishi Chariot,Mitsubishi Challenger,Mitsubishi Carisma,Mitsubishi Eclipse,Mitsubishi Endeavor,Mitsubishi Galant,Mitsubishi Lancer,Mitsubishi Outlander,Mitsubishi Raider,