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Home >> Alfa Romeo >> 2019 >> 4C >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> 1.8L - DTCS P04DB-00 To U1518-00 >> DTC Troubleshooting >> P2251-00-O2 Sensor 1/1 Negative Current Control Circuit/Open >> Possible Causes

Possible Causes

Possible Causes
POOR UPSTREAM O2 SENSOR WIRING CONTINUITY
POOR UPSTREAM O2 SENSOR WIRING INSULATION
LOOSE CONNECTIONS AT THE UPSTREAM O2 SENSOR
LOOSE CONNECTIONS AT THE POWERTRAIN CONTROL MODULE (PCM)
EXHAUST MANIFOLD LEAK
UPSTREAM O2 SENSOR CONTAMINATED OR FOULED
UPSTREAM O2 SENSOR
POWERTRAIN CONTROL MODULE (PCM)