P0641 SAAB - 5 Volt Reference Voltage Incorrect
- 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 or lower than expected
- Engine Light ON (or Service Engine Soon Warning Light)
P0641 Saab 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.