O2 Sensor Pumping Current Trim Circuit High Bank 1 Sensor 1

Where it lives

For P2628, the circuit described runs through the sensor. The description of P2628 puts it on bank 1.

Check these first

• A faulty wideband air/fuel ratio sensor
• An open or high-resistance pumping current circuit
• Sensor contamination from coolant or oil
• Water intrusion in the sensor connector

What to do next

1. Inspect the sensor connector for water, corrosion, or damaged pins
2. Check the pumping current circuit wiring for opens
3. Compare sensor current readings against a known-good reference
4. Check for exhaust leaks near the sensor
5. Replace the air/fuel ratio sensor if the current stays high
6. Clear the code and retest

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