P0139 2014 Toyota RAV4 Code - Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2
Quick Answer
In order to obtain a high purification rate of the Carbon Monoxide (CO), Hydrocarbon (HC), and Nitrogen Oxide (NOx) components in the exhaust gas, a Three-Way Catalytic Converter (TWC) is used. Common causes include Faulty Oxygen Sensor Bank 1 Sensor 2, Oxygen Sensor Bank 1 Sensor 2 harness is open or shorted, Oxygen Sensor Bank 1 Sensor 2 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
- What it means
- P0139 2014 Toyota RAV4 indicates Oxygen Sensor Circuit Slow Response Bank 1 Sensor 2.
- Common causes
- Common causes include Faulty Oxygen Sensor Bank 1 Sensor 2, Oxygen Sensor Bank 1 Sensor 2 harness is open or shorted, Oxygen Sensor Bank 1 Sensor 2 circuit poor electrical connection.
- Severity
- Moderate - service should be scheduled soon.
- Can I drive?
- The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Code P0139 2014 Toyota RAV4 Description
The heated oxygen sensor is located behind the TWC and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).
When the air-fuel ratio becomes lean, the oxygen concentration in the exhaust gas is high. The heated oxygen sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. less than 0.45 V).
Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel level, the oxygen concentration in the exhaust gas is low. The heated oxygen sensor informs the ECM that the post-TWC air-fuel ratio is rich (high voltage, i.e. more than 0.45 V). The heated oxygen sensor has the property of changing its output voltage drastically when the air-fuel ratio is close to the stoichiometric level.
The ECM uses the supplementary information from the heated oxygen sensor to determine whether the air-fuel ratio after the TWC is rich or lean and adjusts the fuel injection duration accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air-fuel ratio control.
The ECM continuously monitors the heated oxygen sensor output voltage while the engine is running. The sensor output voltage drops to below 0.2 V (extremely lean status) immediately when the vehicle decelerates, and the fuel cut is operating. If the voltage does not drop to below 0.2 V for 7 seconds or more, the ECM determines that the sensor response has deteriorated, illuminates the MIL, and stores a Diagnostic Trouble Code (DTC).
What are the Possible Causes of the DTC P0139 2014 Toyota RAV4?
- Faulty Oxygen Sensor Bank 1 Sensor 2
- Oxygen Sensor Bank 1 Sensor 2 harness is open or shorted
- Oxygen Sensor Bank 1 Sensor 2 circuit poor electrical connection
- Gas leak from exhaust system
How to Fix the DTC P0139 2014 Toyota RAV4?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0139 2014 Toyota RAV4 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about P0139 2014 Toyota RAV4 Code
What does OBDII code P0139 mean for a 2014 Toyota RAV4?
P0139 indicates a slow response time from the oxygen sensor located on Bank 1, Sensor 2, which monitors the efficiency of the catalytic converter.
What are the common symptoms of code P0139 in a 2014 Toyota RAV4?
Symptoms may include reduced fuel economy, a check engine light, rough idling, or increased emissions.
What causes code P0139 in a 2014 Toyota RAV4?
Common causes include a faulty downstream oxygen sensor, exhaust leaks, wiring issues, or contamination of the sensor from oil or coolant.
How can I diagnose code P0139 on my 2014 Toyota RAV4?
Use an OBDII scanner to confirm the code, inspect the oxygen sensor and wiring for damage, and check for exhaust leaks or other related issues.
Can I drive my 2014 Toyota RAV4 with code P0139?
While the vehicle may still be drivable, driving with this code can lead to reduced efficiency and possible long-term damage to the catalytic converter.
How do I fix code P0139 on a 2014 Toyota RAV4?
Repairs may involve replacing the downstream oxygen sensor, repairing damaged wiring, or fixing exhaust leaks.
How much does it cost to fix code P0139 on a 2014 Toyota RAV4?
Replacing the oxygen sensor typically costs between $150-$300, depending on parts and labor. Additional repairs like exhaust fixes may increase costs.
Can a dirty oxygen sensor cause code P0139 in a 2014 Toyota RAV4?
Yes, contamination from oil, coolant, or carbon buildup can slow the sensor's response and trigger this code.
Will clearing the code P0139 fix my 2014 Toyota RAV4?
Clearing the code will temporarily remove the check engine light, but the underlying issue must be resolved to prevent the code from returning.
How often should oxygen sensors be replaced on a 2014 Toyota RAV4?
Oxygen sensors typically last 60,000 to 100,000 miles, but premature failure can occur due to contamination or other issues.
Discuss the causes and fixes for P0139 2014 Toyota RAV4 OBDII Code
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