P0137
Low SeverityO2 Sensor Circuit Low Voltage (Bank 1, Sensor 2)
Emissions System
What Does P0137 Mean?
Downstream O2 sensor on bank 1 is reading too low. Could indicate a failing sensor or a lean exhaust condition.
Common Fix
Replace downstream O2 sensor
Estimated Cost (DIY)
$25 - $80
Symptoms
- ⚠️Check engine light
- ⚠️Failed emissions test
- ⚠️Possible P0420 code
Related Symptoms
Common Causes
How to Diagnose P0137
- 1Check for exhaust leaks after catalytic converter
- 2Monitor sensor voltage
- 3Compare upstream and downstream readings
- 4Replace sensor if stuck low
OEM Diagnostic Flowchart
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Related Resources
Repair guides, symptom pages, and wiring diagrams related to P0137.
OEM Manual Evidence
Browse →A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali AWD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL Denali 2WD V8-6.2L Service Manual | Operation CHARM Operation CHARM : Car...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-6.0L Service Manual | Operation CHARM Operation CHARM : Car repair...
A L L Diagnostic Trouble Codes ( DTC ) — 2013 GMC Truck Yukon XL 4WD V8-5.3L Service Manual | Operation CHARM Operation CHARM : Car repair...
Related Symptoms
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Related Codes
General fault with the downstream (post-cat) O2 sensor on bank 1. This sensor monitors catalytic converter efficiency.
Downstream O2 sensor bank 1 is stuck at a high voltage. Usually a failed sensor.
The catalytic converter on bank 1 is not converting pollutants efficiently. This is one of the most common DTCs.
Frequently Asked Questions
- Can P0137 mean the catalytic converter is bad?
- Not usually — P0137 is more likely the sensor itself. P0420 is the code that indicates catalytic converter efficiency issues.
- Should I replace both O2 sensors?
- Not necessarily. Only replace the one that has failed. However, if both are original and high-mileage, replacing both saves labor.
Related Repair Guides
If your vehicle has triggered P0137, these DIY repair guides may help: