– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 harness is open shorted
– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit poor electrical connection
– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 fuse
– Faulty Engine Control Module (ECM)
The heated oxygen (HO2S) bank 2 sensor 1 is threaded into the exhaust manifold. The sensor is equipped with a heater element to decrease the amount of time required to enter closed loop fuel control. The Engine Control Module (ECM) controls the heater by pulsing circuit 551 to ground. When the heater is commanded Off (circuit not grounded), the voltage level at the ECM should be high (ignition voltage). When the heater is commanded On (circuit grounded), the voltage level at the ECM should be low. The ECM heater feedback circuit uses a pull-up voltage (1.6-3.6 volts), which allows the ECM to individually differentiate between an open, short to ground or short to voltage.