O2 Sensor Reference Voltage Circuit (Bank 1 Sensor 1)
The P2246 code means the vehicle's onboard diagnostic system has detected: O2 Sensor Reference Voltage Circuit (Bank 1 Sensor 1). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $100 - $400 (parts and labor)
Best-selling code reader on Amazon. Reads and clears check engine codes on any 1996+ vehicle. Under $30.
Essential for diagnosing sensor codes, checking voltage, and testing circuits. Under $15 and pays for itself on the first job.
Affiliate links — we earn a commission at no extra cost to you.
What Are the Symptoms of P2246?
- Check Engine Light on
- Engine runs poorly
- Rich or lean condition
- Failed emissions test
- Rough idle
What Causes P2246? (Most Likely First)
- Failed O2 sensor heater or internal reference Very High
- Wiring fault in O2 sensor reference circuit High
- ECM O2 reference output circuit fault Moderate
- Corroded O2 sensor connector affecting reference Low
Can I Still Drive with P2246?
Short distances only. P2246 is rated moderate severity. Keep trips short and get it diagnosed soon rather than waiting for symptoms to worsen.
Frequently Asked Questions
What is the O2 sensor reference voltage?
The ECM provides a reference voltage (typically 2.5V or 3.3V) to the wideband O2 sensor to establish a baseline for measuring oxygen content in the exhaust.
Can a bad ECM cause this code?
It is possible but rare. The vast majority of these codes are caused by a failed O2 sensor or wiring issue. Test the sensor and wiring thoroughly before considering ECM replacement.
Do I need a special tool to test this?
A multimeter can measure reference voltage and resistance. A scan tool with live data capability is also very helpful for monitoring O2 sensor operation in real time.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose P2246?
-
Measure O2 sensor reference voltage at the sensor connector
-
Check ECM reference output at the ECM connector
-
Inspect wiring between ECM and O2 sensor for damage
-
Replace O2 sensor if reference circuit within sensor is faulty
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
Which Vehicles Commonly Get P2246?
- 2010-2020 Toyota Camry 2.5L
- 2012-2019 Honda Civic 2.0L
- 2008-2018 Ford F-150 5.0L
- 2011-2020 Chevrolet Silverado 5.3L
Explore More
Was this helpful?
Send this to whoever is fixing the car — your mechanic, or the person asking what the light means.