P0138 2008 Toyota Camry Code - Oxygen Sensor Circuit High Voltage 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 TWC is used. Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, EFI Relay, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted. 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
- P0138 2008 Toyota Camry indicates Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2.
- Common causes
- Common causes include Faulty Rear Heated Oxygen Sensor Bank 1, EFI Relay, Rear Heated Oxygen Sensor Bank 1 harness is open or shorted.
- 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 P0138 2008 Toyota Camry Description
The HO2 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 rich. The HO2 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 becomes lean. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is rich (high voltage, i.e. more than 0.45 V). The HO2 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 HO2 sensor to determine whether the air-fuel ratio after the TWC is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the HO2 sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air-fuel ratio control.
What are the Possible Causes of the DTC P0138 2008 Toyota Camry?
- Faulty Rear Heated Oxygen Sensor Bank 1
- EFI Relay
- Rear Heated Oxygen Sensor Bank 1 harness is open or shorted
- Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
- Intake air leaks
- Exhaust gas leaks
- Inappropriate fuel pressure
- Faulty fuel injectors
How to Fix the DTC P0138 2008 Toyota Camry?
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
There is a factory service bulletin for the following Toyota model:
2008 Toyota Camry
2008 Toyota Camry Service Bulletin OBDII Code P0138
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0138 2008 Toyota Camry 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.
Need more information about the P0138 2008 Toyota Camry code?
Need more information on how to fix the P0138 2008 Toyota Camry code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0138 2008 Toyota Camry code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0138 2008 Toyota Camry Code
1. What are the common symptoms of OBDII code P0138 on a 2008 Toyota Camry?
- Common symptoms include poor fuel economy, rough idling, engine misfires, and the illumination of the Check Engine Light.
2. What does the OBDII code P0138 Oxygen Sensor Circuit High Voltage Bank 1 Sensor 2 mean for a 2008 Toyota Camry?
- This code indicates that the oxygen sensor downstream of the catalytic converter on bank 1 is detecting a high voltage condition.
3. What are the possible causes of OBDII code P0138 on a 2008 Toyota Camry?
- Possible causes include a faulty oxygen sensor, wiring issues in the oxygen sensor circuit, a vacuum leak, exhaust leaks, or a problem with the catalytic converter.
4. How can I diagnose the cause of OBDII code P0138 on my 2008 Toyota Camry?
- Diagnosing this code typically involves checking the oxygen sensor's voltage readings, inspecting the sensor's wiring for damage, and performing a thorough inspection of the exhaust system for leaks.
5. Can driving with OBDII code P0138 on a 2008 Toyota Camry cause further damage?
- Continuing to drive with this code may lead to decreased fuel efficiency and potential damage to the catalytic converter over time.
6. How can I repair OBDII code P0138 on a 2008 Toyota Camry?
- Repair options include replacing the oxygen sensor Bank 1 Sensor 2, repairing any damaged wiring, fixing exhaust leaks, and addressing any other underlying issues that may have triggered the code.
7. Is it safe to ignore OBDII code P0138 on a 2008 Toyota Camry?
- It is not recommended to ignore this code, as it can lead to reduced engine performance, increased emissions, and potential long-term damage to the vehicle's components.
8. Can a DIY enthusiast fix OBDII code P0138 on a 2008 Toyota Camry?
- While some repairs related to this code can be done by DIY enthusiasts, diagnosing and fixing complex issues may require professional expertise and specialized tools.
9. How much does it typically cost to repair OBDII code P0138 on a 2008 Toyota Camry?
- The cost of repairing this code can vary depending on the underlying issue, but it may range from $100 to $500 or more, including parts and labor.
10. How often does OBDII code P0138 occur in a 2008 Toyota Camry?
- The occurrence of this code can vary, but it is relatively common in vehicles with high mileage or those exposed to harsh driving conditions. Regular maintenance and timely repairs can help prevent it.
Discuss the causes and fixes for P0138 2008 Toyota Camry OBDII Code
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Did you use factory sensors? There is a service bulletin for that code. The bulletin suggest replacing the sensor with special parts numbers. See "Tech Notes" above for more information
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