Circuit/System Verification
Attempt to communicate with all modules on the high speed GMLAN bus.
- If any high speed module communicates and any DTC beginning with a U exists, refer to Diagnostic Trouble Code (DTC) List - Vehicle for diagnostics.
- If any high speed module communicates and no DTC beginning with a U exists, refer to DTC U0100-U0299 or U2105-U2199 for diagnostics.