K 2500 Truck 4WD V8-5.3L VIN T (1999)
After reprogramming, test for DTCs in the ECCM. When only DTCs which begin with a U are set with a history status, clear the DTCs.
Otherwise, diagnose the malfunction using the appropriate diagnostic table.
TEST DESCRIPTION
1. This step verifies that the module which does not communicate is powered and will not communicate via the class 2 serial data link.
2. This test inspects for an improper connection to the module preventing class 2 serial communication.
3. This test determines whether the malfunction is due to the class 2 serial data circuit or due to a malfunction control module.
4. This test inspects for an improper connection to SP205 preventing class 2 serial communication.
5. This test determines whether the malfunction is due to the class 2 serial data circuit or due to a malfunction in splice pack SP205.
10. The module which did not communicate due to a class 2 serial data circuit malfunction will have set Lost Communication DTCs for those modules
that the module was monitoring.
12. Since the modules which can communicate indicate the module which cannot communicate, it is necessary to clear the DTC from these modules in
order to avoid future misdiagnosis.
Scan Tool Does Not Communicate With UART Data Line (Part 1 Of 2)
