I have Code P0641 on my 2007 Chevy 1500, Where should I start?
Check your connections at the computer and the wiring harness. If all checks out you will most likely need to replace the ECM itself.
P0641 CHEVROLET – 5 Volt Reference Voltage Incorrect
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.
– ECM harness is open or shorted
– ECM circuit poor electrical connection
– Shorted sensor on 5 volt circuit