Alternator output and power demand of all electrical loads and systems must be matched to each other as ideally as possible so that the entire system is reliable and trouble-free in operation. The ECM monitors alternator output deviation from the signal of the FR terminal of the alternator when the engine is running.
P0620 is set when alternator control circuit is open or short at IG "ON"
Item
Detecting Condition
Possible cause
DTC Strategy
Signal Monitoring
Control circuit is open or short
Poor connection or damaged harness
Enable Conditions
IG "ON"
Threshold value
Signal circuit is open or short
Diagnosis Time
1sec
MIL On Condition
OFF