Why is my scan tool not communicating with all modules?
Why is my scan tool not communicating with all modules? If your scan tool doesn’t automatically communicate with all modules, you must manually poll each module to determine if that module is reporting. If your scan tool indicates “no communication” with a specific module, then you must diagnose the reason for the non-communication. What to do if the OBD II scanner doesn't communicate with the vehicle? What to do if the OBD II scanner doesn’t communicate with the vehicle. TEST 1: Connect the positive DMM lead to DLC pin 4 and the negative DMM lead to the negative battery terminal,...