P0155 TOYOTA O2 Sensor Heater Circuit Bank 2 Sensor 1

Possible causes
– Faulty Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1
– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit fuse
– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 harness is open shorted to ground
– Heated Oxygen Sensor (H2OS) Bank 2 Sensor 1 circuit poor electrical connection
– Faulty Engine Control Module (ECM)
Tech description
The code means that there is a problem with the heater element circuit of the heated oxygen sensor. The Engine Control Module (ECM) monitors how long it take the sensor to warm up and start sending an adequate signal. The code means the the sensor is taking too long to warm up. Replacing the Front Heated Oxygen Sensor (H2OS) Bank 2 usually takes care of the problem.
When is the obd code mean?
The current amperage in the front heated oxygen sensor heater circuit is out of the normal range. (An improper voltage drop signal is sent to ECM through the front heated oxygen sensor heater)
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
– Possible higher fuel consumption
– Possible more smoke from exhaust than usual
P0155 TOYOTA OBD Code Description