P0155
Low SeverityO2 Sensor Heater Circuit (Bank 2, Sensor 1)
Emissions System
What Does P0155 Mean?
Heater failure in the upstream O2 sensor on bank 2.
Common Fix
Replace O2 sensor
Estimated Cost (DIY)
$30 - $100
Symptoms
- ⚠️Check engine light
- ⚠️Slightly worse fuel economy cold
- ⚠️Failed emissions
Related Symptoms
Common Causes
How to Diagnose P0155
- 1Check O2 heater fuse
- 2Measure heater resistance
- 3Inspect wiring
- 4Replace sensor
OEM Diagnostic Flowchart
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0155.
OEM Manual Evidence
Browse →A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Acadia FWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repair ma...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Acadia AWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repair ma...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 Chevy Truck Traverse AWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repai...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 Chevy Truck Traverse FWD V6-3.6L Service Manual | Operation CHARM Operation CHARM : Car repai...
Related Symptoms
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Related Codes
The heater in the upstream O2 sensor on bank 1 is not working properly. The heater brings the sensor to operating temperature quickly.
The oxygen sensor heater circuit on the upstream (pre-cat) sensor of bank 1 has a fault. The heater gets the O2 sensor to operating temperature quickly for proper fuel trim.
Heater failure in downstream O2 sensor bank 2.
Frequently Asked Questions
- Is the bank 2 O2 sensor different from bank 1?
- Often yes — bank 1 and bank 2 upstream sensors may have different part numbers due to wire length or connector style.
- Can I use universal O2 sensors?
- Yes, but you must splice the wires correctly. Direct-fit sensors are easier and more reliable.
Related Repair Guides
If your vehicle has triggered P0155, these DIY repair guides may help: