TorqueMech Beta
TorqueMech OBD Code Guide

P0140 - O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)

An oxygen sensor circuit issue was detected.

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Code Meaning

An oxygen sensor circuit issue was detected.

Common Causes

O2 sensor aging/failure
Wiring/connectors damage
Exhaust leak upstream
Engine running rich/lean affecting readings

Quick Checks

  • Check for exhaust leaks near manifold
  • Inspect O2 sensor wiring away from hot exhaust
  • Verify heater fuse/relay (if heater code)
  • Check fuel trims/misfires first

Likely Repairs

Use test results to confirm the fault before pricing the repair.

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Related Codes

P0420
Catalyst Efficiency Below Threshold (Bank 1)
Open ->
P0430
Catalyst Efficiency Below Threshold (Bank 2)
Open ->
P0137
O2 Sensor Circuit Low Voltage (Bank 1 Sensor 2)
Open ->
P0138
O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
Open ->

Next Steps

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