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Home >> Ford >> 2023 >> Escape ST-Line Select >> Repair and Diagnosis >> External Pages >> Different car >> Section 12 (Engine Controls - Powertrain DTC Charts & Descriptions (Diesel)) >> Diagnostic Trouble Code (DTC) Charts And Descriptions >> DTC P0139 - O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)
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DTC P0139 - O2 Sensor Circuit Slow Response (Bank 1 Sensor 2)

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P0139 - O2 SENSOR CIRCUIT SLOW RESPONSE (BANK 1 SENSOR 2)

Description:  The nitrogen oxides bank 1, sensor 2 (NOx12) module monitors the NOx12 sensor oxygen (O2) response time during the transition from an engine load to deceleration fuel shut off (DFSO). This DTC sets when the actual O2 signal value does not reach a predicted O2 signal value within a calibrated amount of time.
Possible Causes: 
  • Corrosion
  • Incorrect connections
  • Contaminated NOx12 sensor
  • Damaged NOx12 sensor
Diagnostic Aids:  The presence of this DTC may indicate that the vehicle is operating in derate mode and may experience a loss of power. After repair, the vehicle may still display a system warning message. Drive the vehicle until the system warning message has cleared from the instrument cluster message center.
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All GO to PINPOINT TEST RD .