NOx Sensor Supply Voltage Circuit Bank 1 Sensor 1

Where it lives

For P220A, the sensor sits on the circuit this code reports. The description of P220A puts it on bank 1.

Check these first

• An open or shorted supply voltage wire feeding bank 1 sensor 1
• Corrosion or water in the bank 1 sensor 1 connector
• A failed bank 1 sensor 1 drawing too much current and pulling the feed down
• Low charging system voltage dropping below the sensor minimum
• A weak driver in the ECM for the bank 1 sensor 1 supply

What to do next

1. Check battery and charging voltage at idle and under load
2. Inspect the bank 1 sensor 1 connector for corrosion or water
3. Measure supply voltage at the bank 1 sensor 1 connector with the key on
4. Test the supply wire for opens and shorts to ground
5. Replace bank 1 sensor 1 if the supply is present but the sensor stays dead
6. Clear the code and retest

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