OBDII Code List

P305B BUICK - DC/DC Converter Ignition On/Start Switch Circuit High Voltage

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
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Possible causes

  • Faulty Power Supply Transformer
  • Power Supply Transformer harness is open or shorted
  • Power Supply Transformer circuit poor electrical connection

Possible symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)

P305b Buick Description

The Body Control Module (BCM) controls the ignition main relay through the control circuit by applying voltage to the circuit. The power supply transformer samples the system voltage on the Ignition 1 voltage circuit from the ignition main relay. If the Power Supply Transformer detects a fault in the circuit it will request the Engine Control Module (ECM) to set the Diagnostic Trouble Code (DTC) and illuminate the Malfunction Indicator Light/Lamp (MIL).
OBDII Code P305b Buick - DC/DC Converter Ignition On/Start Switch Circuit High Voltage -

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