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P1646 Code – HO2 Sensor Control Malfunction Bank 1 Upstream

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Code P1646 Possible Causes
Faulty Upstream HO2 Sensor Bank 1
Upstream HO2 Sensor Bank 1 circuit poor electrical connection
Upstream HO2 Sensor Bank 1 harness is open or shorted
Faulty Powertrain Control Module PCM

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