P0643 FORD - Sensor Reference Voltage 'A' Circuit High

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

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

When is the code detected?

The Engine Control Module (ECM) 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 Ford Description

The control module has 2 internal 5-volt reference buses called 5-volt reference 1 and 5-volt reference 2 . Each reference bus provided 5-volt reference circuit for more than one sensor. Therefore, a fault condition on one 5-volt reference circuit will affect the other 5-volt reference circuits connected to the reference bus. The control module monitors the voltage on the 5-volt reference buses.
OBDII Code P0643 Ford - Sensor Reference Voltage 'A' Circuit High - AutoCodes.com

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P0643 FORD Comments

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