G 20 3/4 Ton Van L6-250 4.1L VIN D 2-bbl (1984)
1984 COMPUTER COMMAND CONTROL "S/T" AND "G" VANS
This condition can be caused by an electrical feedback from the generator light circuit back to the ECM. This condition can be corrected by installing a
diode jumper assembly (see illustration), P/N 12047479, between the generator and the existing harness.
Before this diode jumper assembly is installed, it should be determined that it is a false code and not a legitimate EST problem.
Refer to the service manual for diagnosis of trouble codes.