Engine-Codes - Ford - P0139 2012 Ford Fusion

P0139 2012 Ford Fusion Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 2

- Code Popularity: 2,976 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0139 2012 Ford Fusion?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Rear Heated Oxygen Sensor Bank 1
  • Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
  • Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
  • Inappropriate fuel pressure
  • Faulty fuel injectors
  • Intake air leaks may be faulty
  • Exhaust gas leaks

Code Tech Notes

Replacing the Rear Heated Oxygen Sensor Bank 1 usually takes care of the problem.

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How to Fix the DTC P0139 2012 Ford Fusion?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P0139 2012 Ford Fusion code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

When is the Code Detected?

The P0139 code is set when the Engine Control Module (ECM) detects that the rear O2 sensor takes more time to respond between rich and lean than the specified time.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)
  • High Fuel Consumption
  • Excessive Smoke from Exhaust

What Does the P0139 2012 Ford Fusion Code Mean?

The heated oxygen sensor (HO2S) monitor tracks the rate of voltage change during the rise and fall of the HO2S signal. When the rate of voltage change is less than a calibrated value, the Powertrain Control Module (PCM) begins to modify the fuel trim attempting to increase the HO2S voltage switch rate. The DTC sets when the PCM is at the allowable limit or has exceeded an allowable length of time for fuel trim modification, without detecting an acceptable rate of voltage change.

P0139 2012 Ford Fusion Code - O2 Sensor Circuit Slow Response Bank 1 Sensor 2

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