C 3500 HD Truck 2WD V8-6.5L DSL Turbo VIN F (2001)
4. A State of Health DTC with a history status may be present along with a U1000 or U1255 having a current status. This indicates that the
malfunction occurred when the ignition was ON.
5. DLC terminal 2 and terminal 5 provide the connection to the class 2 serial data circuit and the signal ground circuit respectively.
7. A poor connection at terminal A would cause this condition but will not set a DTC.
8. An open in the class 2 serial data circuit will prevent the scan tool from communicating with the module. This condition will not set a DTC.
9. This test isolates the PCM class 2 serial data circuit.
10. This test isolates the EBCM class 2 serial data circuit.
11. This test isolates the VTD class 2 serial data circuit.
14. If there are no current DTCs that begin with a U, the communication malfunction has been repaired.
15. The communication malfunction may have prevented diagnosis of the customer complaint.
Scan Tool Does Not Communicate With EBCM
TEST DESCRIPTION FOR UART SERIAL DATA LINE
Steps 1-8