P0155 – O2 Sensor Heater Circuit (Bank 2 Sensor 1)
Description
The ECM detects a malfunction in the heater circuit of the upstream O2 sensor on Bank 2.
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Compare Diagnostic ScannersSymptoms
- Poor fuel economy
- Rough idle
- Extended time to closed loop
- Check engine light
Causes
- Failed heater element
- Blown fuse
- Open or shorted wiring
- Connector corrosion
Diagnosis
- Check heater fuse and power feed
- Measure heater resistance
- Verify power and ground at sensor
- Inspect harness for chafing or damage
Repair
- Replace O2 sensor if heater is out of spec
- Repair or replace wiring
- Replace fuse after fixing root cause
