P0137 meaning: O2 Sensor Low Voltage (Bank 1 Sensor 2) Explained
Learn what P0137 means, its most common causes, live scan PIDs, DIY checks, and when to consult a specialist.
P0137 meaning: O2 sensor low voltage (bank 1 sensor 2) indicates the downstream oxygen sensor on the first exhaust bank is reporting abnormally low voltage to the engine control module. This code appears when the sensor signal drops below expected thresholds during normal operation.
At a glance
| Severity | Can you keep driving? | DIY difficulty | Typical fix path |
|---|---|---|---|
| moderate — fix soon | short trips only | varies | sensor replacement or wiring repair |
Definition and live scan PIDs
The P0137 code triggers when the downstream O2 sensor on bank 1 fails to maintain sufficient voltage, typically signaling a rich exhaust condition or sensor failure. During a live scan, you’ll see PID 01 42 (O2 Sensor Voltage - Bank 1 Sensor 2) reporting values consistently below 0.2 volts, while adjacent PIDs like 01 43 (O2 Sensor Voltage - Bank 1 Sensor 3) remain stable. No other codes usually accompany it unless related issues exist.
Most common causes
- Faulty downstream O2 sensor is the primary culprit, often due to aging or contamination.
- Damaged wiring or poor connections between the sensor and control module can interrupt signals.
- Exhaust leaks upstream of the sensor may cause false lean readings that the ECU misinterprets.
- Rarely, a malfunctioning powertrain control module may misread sensor data.
DIY-safe check
Inspect the sensor’s wiring harness for corrosion, fraying, or disconnection at both the sensor and ECU ends. Ensure the connector is seated securely and no pins are bent. If wiring appears intact, the sensor itself likely requires replacement — this is a common fix for P0137.
When to consult a specialist
If the wiring check reveals no issues but the code persists, or if multiple O2 sensor codes appear simultaneously, professional diagnosis is recommended. Specialists can perform advanced tests like scope analysis to rule out subtle electrical faults or PCM issues.
Related resources
If you’re troubleshooting multiple codes, P0123 meaning: Throttle Position Sensor A Circuit High Input Explained · OBD2 Online offers guidance on P0123 meaning for throttle position sensor issues. For broader context on oxygen sensor circuits, P0117 meaning: ECT Sensor Circuit Low Input Explained · OBD2 Online explains P0117 meaning in coolant temperature sensor failures. To explore all OBD code references, Cars specialists leads to our category of cars specialists.
FAQ
What does P0137 mean?
P0137 indicates the downstream oxygen sensor on bank 1 is detecting low voltage output, suggesting the exhaust mixture may be too rich or the sensor is failing.
Can I keep driving with this code?
Short-term driving is usually possible but not advised — prolonged operation may damage the catalytic converter or reduce fuel efficiency.
How much does it cost to fix P0137?
Repair costs vary widely based on vehicle make and labor rates, typically ranging from $150 to $400 for sensor replacement.
Can I fix P0137 myself?
Yes, if you can safely access and replace the sensor with basic tools, but electrical diagnostics often require professional equipment to confirm the root cause.
Talk to a specialist today to resolve P0137 safely and restore your vehicle’s performance. a verified specialist