P0138 2018 GMC Sierra Code - HO2S Circuit High Voltage Bank 1 Sensor 2
Quick Answer
The code P0138 for a 2018 GMC Sierra refers to a fault in the HO2S (Heated Oxygen Sensor) circuit on Bank 1 Sensor 2, indicating that the oxygen sensor is reading a high voltage. Common causes include Faulty oxygen sensor, Damaged wiring or connectors, Exhaust leaks. 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 2018 GMC Sierra indicates HO2S Circuit High Voltage Bank 1 Sensor 2.
- Common causes
- Common causes include Faulty oxygen sensor, Damaged wiring or connectors, Exhaust leaks.
- 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 P0138 2018 GMC Sierra Description
The code P0138 for a 2018 GMC Sierra refers to a fault in the HO2S (Heated Oxygen Sensor) circuit on Bank 1 Sensor 2, indicating that the oxygen sensor is reading a high voltage. The oxygen sensor is responsible for measuring the oxygen content in the exhaust gases and sending this information to the engine control module (ECM) to adjust the air-fuel mixture for optimal combustion. The Bank 1 Sensor 2 is located downstream of the catalytic converter in the exhaust system.
Common Causes of P0138 2018 GMC Sierra
- Faulty oxygen sensor
- Damaged wiring or connectors
- Exhaust leaks
- ECM issues
- Contaminated fuel
Symptoms of P0138 2018 GMC Sierra
- Decreased fuel efficiency
- Engine misfires or hesitation
- Rough idling or stalling
- Check Engine Light illuminated
- Failed emissions test
How to Fix P0138 2018 GMC Sierra
- Begin by diagnosing the specific issue causing the high voltage reading using a scan tool to monitor the oxygen sensor's output.
- Inspect the oxygen sensor, wiring, and connectors for any visible damage or corrosion. Replace any damaged components.
- Check for exhaust leaks near the sensor and repair as necessary.
- Clear the fault code from the ECM memory and perform a test drive to ensure the issue has been resolved.
- If the problem persists, further testing may be required to pinpoint the exact cause, such as testing the ECM or performing a smoke test to detect any hidden leaks.
Cost to Fix P0138 2018 GMC Sierra
The cost of repairing a P0138 code on a 2018 GMC Sierra can vary depending on the underlying cause of the issue. On average, the cost of replacing an oxygen sensor ranges from $200 to $300, including parts and labor. However, if the problem is related to wiring or ECM issues, the cost could be higher due to additional diagnostic time and potential part replacements. It's recommended to consult with a qualified mechanic or auto repair shop for an accurate estimate based on your specific vehicle and location. Keep in mind that labor rates and diagnostic fees can vary, so it's advisable to inquire about these costs upfront.
Tech Notes for P0138 2018 GMC Sierra
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