M
p0137
Moderate
Mercedes-Benz · SUVs
O2 Sensor Circuit Low Voltage Bank 1 Sensor 2
Quick Answer
Error code P0137 on your Mercedes-Benz SUVs means: O2 Sensor Circuit Low Voltage Bank 1 Sensor 2. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
  1. Failed downstream oxygen sensor on Bank 1
  2. Exhaust leak near the downstream sensor location
  3. Wiring short or open circuit in the O2 sensor harness
  4. Water or road debris damage to the sensor connector
  5. Contaminated sensor element from coolant or oil leak
How to Fix It
1
Monitor the Bank 1 Sensor 2 O2 voltage with a scan tool under various conditions
2
Inspect the O2 sensor wiring harness and connector for physical damage
3
Check for exhaust leaks around the sensor bung and surrounding pipe joints
4
Test the O2 sensor heater circuit for proper resistance and power supply
5
Replace the downstream O2 sensor if voltage remains fixed at low reading
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Downstream O2 sensor (Bank 1 Sensor 2)
O2 sensor socket
Anti-seize compound
Wiring repair connectors
Related Error Codes
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