P0138 – O2 Sensor Circuit High Voltage (Bank 1 Sensor 2)
Description
The downstream O2 sensor is reporting a high voltage signal.
Need More Than Just the Fault Code?
A diagnostic scanner with live data, freeze-frame information and the right system access can help you investigate the actual cause before replacing parts.
Compare Diagnostic ScannersSymptoms
- Rough idle
- Hesitation
- Poor acceleration
- High fuel trims
- Check engine light
Causes
- Rich fuel mixture
- Faulty O2 sensor
- Exhaust leak
- Wiring issue
- Contaminated sensor
Diagnosis
- Inspect O2 wiring
- Check fuel trims
- Inspect exhaust leaks
- Scan live data
- Test sensor response
Repair
- Replace O2 sensor
- Fix exhaust leaks
- Repair wiring
- Check fuel trims
- Address rich mixture
