The purpose of the System Voltage is to detect an excessively low or high system voltage that may be caused by a malfunctioning charging system..
System Voltage is the ignition voltage potential at the Powertrain Control Module (PCM) PCM measures and compares voltage from ignition key and each relay. With this mechanism, PCM knows if the main relay switch turns on after IG on or if turns OFF after IG off.
If the system voltage is below 2.54V during 0.2 sec, PCM sets DTC P0561.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Rationality check
? Poor connection
? Open/short to ground in control circuit
? Charging system
? Main relay
? ECM
Enable Conditions
Threshold Value
? Voltage < 2.54 V
Diagnostic Time
? 0.2 sec
MIL ON Condition
? 2 driving cycle