AutoCodesAcura – P0138 Acura

P0138 Acura Code - Secondary Heated Oxygen Sensor 2 Circuit High Voltage

Quick Answer

The Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) detects the oxygen content in the exhaust gas downstream of the three-way catalytic converter (TWC) during stoichiometric air/fuel ratio feedback control. Common causes include Faulty Secondary Heated Oxygen Sensor 2, Secondary Heated Oxygen Sensor 2 harness is open or shorted, Secondary Heated Oxygen 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
P0138 Acura indicates Secondary Heated Oxygen Sensor 2 Circuit High Voltage.
Common causes
Common causes include Faulty Secondary Heated Oxygen Sensor 2, Secondary Heated Oxygen Sensor 2 harness is open or shorted, Secondary Heated Oxygen 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.
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Code Popularity 23,291
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Aug 14, 2023
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Code P0138 Acura Description

The Secondary Heated Oxygen Sensor (Secondary HO2S (Sensor 2)) detects the oxygen content in the exhaust gas downstream of the three-way catalytic converter (TWC) during stoichiometric air/fuel ratio feedback control. The Powertrain Control Module (PCM) controls the air/fuel ratio from the Air/Fuel Ratio (A/F) Sensor (Sensor 1) output voltage to optimize the TWC efficiency. When power is applied to the Secondary HO2S (Sensor 2) heater, if the Secondary HO2S (Sensor 2) output voltage is high or the SO2SG terminal voltage is high during feedback control, the PCM detects a malfunction and stores a Diagnostic Trouble Code (DTC).
OBDII Code P0138 Acura - Secondary Heated Oxygen Sensor 2 Circuit High Voltage - AutoCodes.com
P0138 Acura Code - Secondary Heated Oxygen Sensor 2 Circuit High Voltage

What are the Possible Causes of the DTC P0138 Acura?

  • Faulty Secondary Heated Oxygen Sensor 2
  • Secondary Heated Oxygen Sensor 2 harness is open or shorted
  • Secondary Heated Oxygen Sensor 2 circuit poor electrical connection

How to Fix the DTC P0138 Acura?

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 P0138 Acura 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 Acura code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0138 Acura Code

1. What are the common symptoms of OBDII code P0138 in an Acura related to the secondary heated oxygen sensor 2 circuit high voltage?

- Common symptoms include poor fuel economy, rough idle, engine hesitation, and the illumination of the check engine light.

2. What are the possible causes of the secondary heated oxygen sensor 2 circuit high voltage code P0138 in an Acura?

- Potential causes include a faulty oxygen sensor, damaged wiring or connectors, exhaust leaks, a malfunctioning catalytic converter, or issues with the engine's fuel system.

3. How can I diagnose the OBDII code P0138 in my Acura related to the secondary heated oxygen sensor 2 circuit high voltage?

- Diagnosis typically involves inspecting the oxygen sensor, checking the wiring and connectors for damage, testing the catalytic converter, and using a scan tool to monitor sensor readings.

4. What repairs can I perform to fix the secondary heated oxygen sensor 2 circuit high voltage code P0138 in my Acura?

- Repair options may include replacing the oxygen sensor, repairing damaged wiring or connectors, fixing exhaust leaks, replacing the catalytic converter if needed, and addressing any fuel system issues.

5. Can I drive my Acura with the P0138 code related to the secondary heated oxygen sensor 2 circuit high voltage?

- It is generally not recommended to continue driving with this code present, as it can lead to reduced fuel efficiency and potentially cause damage to other components of the vehicle over time.

6. How important is it to address the OBDII code P0138 in an Acura related to the secondary heated oxygen sensor 2 circuit high voltage?

- It is crucial to address this code promptly to ensure optimal engine performance, fuel efficiency, and emissions control. Ignoring the issue can lead to more serious problems down the line.

7. Are there any preventive measures I can take to avoid the recurrence of the P0138 code in my Acura?

- Regular maintenance, such as replacing oxygen sensors at recommended intervals, checking for exhaust leaks, and keeping the fuel system in good condition, can help prevent the reoccurrence of this code.

8. How much does it typically cost to repair the secondary heated oxygen sensor 2 circuit high voltage code P0138 in an Acura?

- The cost of repair can vary depending on the specific issue causing the code, the labor rates in your area, and the cost of parts. It is recommended to get a diagnosis from a trusted mechanic for an accurate estimate.

9. Can I reset the check engine light after addressing the P0138 code related to the secondary heated oxygen sensor 2 circuit high voltage in my Acura?

- Yes, once the underlying issue causing the code has been resolved, you can reset the check engine light using an OBDII scanner or by disconnecting the vehicle's battery for a few minutes.

10. How long does it take to repair the secondary heated oxygen sensor 2 circuit high voltage code P0138 in an Acura?

- The repair time can vary depending on the exact cause of the code and the complexity of the repair. It is advisable to consult with a mechanic for an estimate of the repair duration.

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