Circuit/System Verification

Ignition ON. Radio ON.
Verify that DTC U0100-U02FF is set.
- If the DTC is set
  Refer to DTC U0100-U02FF (with HP6) , DTC U0100-U02FF (without HP6) .
- If the DTC is not set
Verify that DTC U2098 or DTC U0029 02 is set.
- If any of the DTCs are set
  Refer to DTC U2098 .
- If none of the DTCs are set
Verify that DTC U0028 is set.
- If the DTC U0028 is set as a current DTC
1. Access the A11 Radio's Last Working MOST ID of Node 1-9 parameters with a scan tool to view MOST device location IDs and MOST bus configuration.
2. Access the A11 Radio's Surrogate MOST Master Node Upstream Position parameter with a scan tool to determine the surrogate MOST Master device and where the MOST ring break occurs. For more information, refer to Diagnostic Aids section.
3. refer to Circuit/System testing (below).
- If the DTC U0028 is set as a history DTC along with other DTCs set
  Diagnose all other DTCs first. Refer to Diagnostic Trouble Code (DTC) List - Vehicle .
- If the DTC U0028 is set as a history DTC with audio or display malfunction and without other DTCs set
1. Access the A11 Radio scan tool data display to record the value of the Surrogate MOST Master Node Upstream Position and the Number of MOST Communication Breaks parameters.
2. Refer to Diagnostic Aids section to help determine the MOST bus configuration, the surrogate MOST Master device and where the MOST ring break occurs to assist in the isolation of intermittent condition.
3. refer to Circuit/System testing (below).
- If the DTC U0028 is not set
Refer to Repair Verification.