O2 Sensor Reference Voltage Circuit Open (Bank 2, Sensor 1)
What does P2243 mean?
The P2243 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Reference Voltage Circuit Open (Bank 2, Sensor 1). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Engine running poorly
- Erratic idle
- Failed emissions test
- Rich or lean condition on Bank 2
Probable Causes (Ranked by Likelihood)
- Open circuit in the O2 sensor reference voltage wiring Very High
- Failed wideband O2 sensor with open reference cell High
- Corroded connector at the Bank 2 Sensor 1 location Moderate
- Damaged wiring from exhaust heat exposure Moderate
- ECM reference voltage output failure Low
Step-by-Step Diagnostic Procedure
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Check for reference voltage at the Bank 2 Sensor 1 connector
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Inspect the wiring from the sensor to the ECM for open circuits
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Test connector pins for corrosion or poor contact
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Check for heat damage to the wiring near exhaust components
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Replace the O2 sensor if internal reference circuit has failed
Frequently Asked Questions
What is the reference voltage circuit in a wideband O2 sensor?
The reference voltage circuit provides a stable baseline voltage to the sensor's Nernst cell, which is used as the reference for measuring the air-fuel ratio.
Can I test the reference voltage with a multimeter?
Yes, with the sensor connected and the engine running, you can measure the reference voltage at the sensor connector. It should be close to 450mV (0.45V) on most systems.
Is P2243 common?
P2243 is less common than basic O2 sensor codes. It is primarily found on vehicles with wideband sensors and typically indicates a sensor or wiring failure rather than an engine running issue.