O2 Sensor Reference Voltage Circuit High (Bank 2, Sensor 1)
The P2245 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Reference Voltage Circuit High (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
- Engine running rich on Bank 2
- Poor fuel economy
- Rough idle or surging
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Short to voltage in the reference voltage wiring Very High
- Failed wideband O2 sensor with high reference output High
- Water intrusion in the sensor connector Moderate
- Signal wire shorted to power wire in the harness Moderate
- ECM reference voltage circuit malfunction Low
Step-by-Step Diagnostic Procedure
-
Measure reference voltage at the sensor connector -- should be approximately 450mV, not higher
-
Check for shorts to power in the reference circuit wiring
-
Inspect the connector for water intrusion or pin damage
-
Look for wires shorted together in the harness
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Replace the O2 sensor if internal failure is confirmed
Frequently Asked Questions
What does high reference voltage indicate?
High reference voltage means the baseline signal to the sensor's Nernst cell is above normal, which causes the sensor to report incorrect air-fuel ratio data to the ECM.
Can moisture cause P2245?
Yes, water intrusion in the sensor connector can create a current path that raises the reference voltage above the expected level.
Is the reference voltage different from the signal voltage?
Yes, the reference voltage is the baseline that the sensor uses internally for measurement. The signal voltage is the output the ECM reads to determine the air-fuel ratio.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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