Test T: Dual Generator Upper Fault Detected (P0620)

PINPOINT TEST T: DUAL GENERATOR UPPER FAULT DETECTED (P0620)

T1-T4:

T4-T6:

T6-T8:

Normal Operation
The generator output is determined by the voltage of the A circuit 35 (OG/LB). The A circuit voltage is compared to a set voltage internal to the voltage regulator and the voltage regulator controls the generator field current to maintain the correct generator output. The set voltage varies with temperature and is typically higher in cold temperatures and lower in warm temperatures.

Possible Causes
- Upper generator C102a disconnected
- B+ circuit fusible links
- B+ circuit 1119 (RD) (upper) open
- A circuit 35 (OG/LB) open
- I circuit 1183 (WH/YE)/904 (LG/RD) open or short to ground
- Upper generator