Lost Communication With Catalyst Temperature Bank 1 Sensor 2

Where it lives

For U0685, start at the sensor the description names. The description of U0685 puts it on bank 1.

Check these first

• Catalyst temperature bank 1 sensor 2 offline on the communication bus
• A broken or shorted wire in the bank 1 sensor 2 circuit
• Corrosion or water in the bank 1 sensor 2 connector
• A failed thermocouple inside bank 1 sensor 2
• Loss of ground or signal return at bank 1 sensor 2

What to do next

1. Check the bank 1 sensor 2 wiring for opens and shorts
2. Inspect the bank 1 sensor 2 connector for corrosion or water
3. Read catalyst temperature live data on bank 1 sensor 2
4. Compare bank 1 sensor 2 with the bank 1 sensor 1 reading
5. Replace catalyst temperature bank 1 sensor 2 if it stays offline
6. Clear the code and retest

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