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DTC P1646: Linear O2 Sensor Control Chip (Bank 1)

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P1646 - LINEAR O2 SENSOR CONTROL CHIP (BANK 1)

Description:  The PCM monitors the application-specific integrated circuit that controls and monitors the heated oxygen sensor (HO2S). This DTC sets when the PCM detects an internal circuit or communication concern.
Possible Causes: 
  • Damaged PCM
Diagnostic Aids:  Internal PCM concern. Reprogram or update the calibration. Check for other DTCs and diagnose those first. Check for aftermarket performance products before installing a new PCM. Clear the DTCs, repeat the self-test. If the DTC is retrieved again, install a new PCM. Refer to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) .
Application  Key On Engine Off  Key On Engine Running  Continuous Memory 
All Refer to the Description, Possible Causes and Diagnostic Aids for the DTC.