Catalyst Temperature Sensor Circuit High Bank 1 Sensor 2

Where it lives

For P042D, the circuit described runs through the sensor. The description of P042D puts it on bank 1.

Check these first

• A rear catalyst temperature sensor on bank 1 reading high
• An open in the rear sensor signal wire
• A poor pin fit at the rear sensor connector
• A converter overheating from a rich condition
• An ECM fault on the rear sensor circuit

What to do next

1. Read the rear sensor voltage on a scan tool
2. Check the rear sensor signal wire for an open
3. Inspect the rear sensor connector pins
4. Check fuel trims and misfire counters
5. Replace the rear sensor if the voltage stays high
6. Clear the code and retest

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