P0602 CHECKSUM ERROR

When Monitored and Set Condition:

When Monitored: While the ignition is on.
Set Condition: A deviation between the ECM memory and a stored calibration.

POSSIBLE CAUSES

• FLASH ECM
• ECM

DIAGNOSTIC PROCEDURE

1. Using the DRBIII®, reflash the ECM with the proper calibration for the particular truck. Is the flash successful?
   Yes --> Repair complete.
   No --> Go To 2
2. With the DRBIII®, read DTCs. Did P0602 set after the reflash?
   Yes --> Replace the ECM.
   No --> Test Complete.