TorqueMech Beta
TorqueMech OBD Code Guide

P0138 - O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)

Downstream O2 sensor signal voltage high (B1S2).

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Code Meaning

Downstream O2 sensor signal voltage high (B1S2).

Common Causes

O2 sensor failure
Wiring short
Rich condition

Quick Checks

  • Check for rich running
  • Inspect wiring
  • Verify sensor output

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

Next Steps

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