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P0139 2005 Scion xB Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2

- Code Popularity: 2,672 Views
- Repair Importance Level: 2/3
- Repair Difficulty Level: 2/3
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What are the Possible Causes of the DTC P0139 2005 Scion xB?

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
⚠ Does your Scion have Safety Recalls? → Check here

How to Fix the DTC P0139 2005 Scion xB?

Review the 'Possible Causes' mentioned above and visually examine the corresponding wiring harness and connectors. Ensure to check for any damaged components and inspect the connector pins for signs of being broken, bent, pushed out, or corroded.

Code Tech Notes

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

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What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0139 2005 Scion xB code, it typically requires 1.0 hour of labor. The specific diagnosis time and labor rates at auto repair shops can differ based on factors such as the location, make and model of the vehicle, and even the engine type. It is common for most auto repair shops to 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

Code P0139 2005 Scion xB Description

The rear Heated Oxygen (HO2) sensor (bank 1 sensor 2) is located behind the Three-Way Catalytic Converter (TWC) and detects the oxygen concentration in the exhaust gas. For optimum TWC operation, the air-fuel mixture must be maintained as close as possible to the stoichiometric ratio. The HO2 sensor output voltage changes dramatically in the vicinity of the stoichiometric ratio. By making adjustments in accordance with these signal voltage changes, the ECM adjusts the fuel injection time so that the air-fuel ratio remains as close as possible to stoichiometric levels. The rear HO2 sensor generates a voltage that ranges from 0.1 V to 0.9 V according to the oxygen concentration in the exhaust gas. When the oxygen concentration in the exhaust gas increases, the HO2 sensor voltage drops below 0.45 V. The ECM interprets this as the air-fuel ratio is lean. Alternatively, the sensor voltage rises to more than 0.45 V when there is no oxygen in the exhaust gas. The ECM interprets this as the air-fuel ratio is rich.

OBDII Code P0139 2005 Scion xB - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2 - AutoCodes.com
P0139 2005 Scion xB Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2

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