P0651 FIAT – Sensor Reference Voltage ‘B’ Circuit/Open

P0651 FIAT Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P0651 FIAT Possible Causes

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

P0651 FIAT 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.