What this code means

The PCM detected a malfunction in the heater circuit of the downstream heated oxygen sensor (Bank 1, Sensor 2).

Symptoms

• Check Engine Light
• Failed emissions test
• Poor catalyst monitoring

Common causes

• Faulty O2 sensor heater
• Blown fuse
• Wiring issue

Diagnostic steps

1. Check fuse
2. Test heater resistance
3. Inspect wiring
4. Check PCM output

Repair notes

Replace downstream O2 sensor or repair wiring.

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