O2 Sensor Reference Voltage Circuit Low Bank 1 Sensor 1
P2245 indicates the PCM detected a low voltage signal from the O2 sensor reference circuit on Bank 2. This code means the oxygen sensor's output voltage is abnormally low, preventing the engine computer from properly reading exhaust oxygen levels needed for fuel trim adjustments.
What You Might Notice
- Illuminated Check Engine light
- Reduced fuel economy
- Diminished engine performance or hesitation
- Rough idle or stumbling during acceleration
- Stored lean or rich condition codes
Most Common Causes
- 1
Faulty O2 Sensor
The oxygen sensor itself may be degraded, contaminated, or failing and unable to generate proper voltage signals. This is the most common cause of reference voltage circuit faults.
- 2
Blown O2 Sensor Fuse
A blown fuse in the O2 sensor circuit prevents proper voltage from reaching the sensor, resulting in consistently low voltage readings.
- 3
Wiring or Connector Issues
Corroded, damaged, or loose wiring and connectors in the O2 sensor circuit can cause poor voltage transmission and signal loss.
- 4
PCM or ECU Malfunction
In rare cases, a defective powertrain control module may misread sensor signals or fail to supply proper reference voltage to the O2 sensor circuit.
How to Diagnose It
- 1
Check Faulty O2 Sensor — The oxygen sensor itself may be degraded, contaminated, or failing and unable to generate proper voltage signals. This is the most common cause of reference voltage circuit faults.
- 2
Check Blown O2 Sensor Fuse — A blown fuse in the O2 sensor circuit prevents proper voltage from reaching the sensor, resulting in consistently low voltage readings.
- 3
Check Wiring or Connector Issues — Corroded, damaged, or loose wiring and connectors in the O2 sensor circuit can cause poor voltage transmission and signal loss.
- 4
Check PCM or ECU Malfunction — In rare cases, a defective powertrain control module may misread sensor signals or fail to supply proper reference voltage to the O2 sensor circuit.
How to Fix It
- 1
Replace O2 Sensor
Remove and replace the Bank 2 oxygen sensor with an OEM or quality aftermarket sensor. Ensure proper installation and connection of all wiring.
- 2
Check and Replace O2 Sensor Fuse
Locate the O2 sensor fuse in the vehicle's fuse box using the owner's manual. Test the fuse with a multimeter and replace if blown with the correct amperage rating.
- 3
Inspect and Repair Wiring
Visually inspect the O2 sensor wiring harness and connectors for corrosion, damage, or loose connections. Clean or repair corroded terminals and ensure all connections are secure.
- 4
Test and Replace PCM if Necessary
After ruling out sensor and wiring issues, use a diagnostic scanner to verify the PCM is supplying correct reference voltage. If voltage is present but the sensor still fails, the PCM may require reprogramming or replacement.
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