O2 Sensor Reference Voltage Circuit Low (Bank 2, Sensor 1)
The P2244 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Reference Voltage Circuit Low (Bank 2, Sensor 1). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $150 - $400 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Poor engine performance
- Engine running lean on Bank 2
- Rough idle
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Short to ground in the reference voltage wiring Very High
- Failed wideband O2 sensor with low reference voltage High
- Corroded connector pulling reference voltage low Moderate
- Damaged wiring with insulation failure Moderate
- ECM reference voltage output issue Low
Step-by-Step Diagnostic Procedure
-
Measure the reference voltage at the sensor connector -- should be approximately 450mV
-
Check for wiring shorts to ground in the reference circuit
-
Inspect connector pins for corrosion or contamination
-
Verify the wiring insulation is intact along the harness
-
Replace the O2 sensor if internal reference has failed
Frequently Asked Questions
What does low reference voltage mean?
Low reference voltage means the baseline signal used by the wideband sensor's Nernst cell is below the expected level, which prevents accurate air-fuel ratio measurement.
Can a ground short cause P2244?
Yes, if the reference voltage wire shorts to ground, the voltage will be pulled low, preventing the sensor from functioning properly.
Should I replace the sensor or check wiring first?
Always check the wiring and connector first. A corroded connector or shorted wire is cheaper to fix than replacing the entire wideband sensor.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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