P0643 GMC - Sensor Reference Voltage 'A' Circuit High

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

  • Faulty Powertrain Control Module (PCM)
  • Powertrain Control Module (PCM) harness is open or shorted
  • Powertrain Control Module (PCM) circuit poor electrical connection
  • Shorted sensor on 5 volt circuit

When is the code detected?

The Powertrain Control Module (PCM) has detected the sensor 5 volt reference circuit voltage is higher than expected

Possible symptoms

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

P0643 Gmc Description

The Powertrain Control Module (PCM) has 2 internal 5-volt reference buses called
OBDII Code P0643 Gmc - Sensor Reference Voltage 'A' Circuit High - AutoCodes.com

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P0643 GMC Comments

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