Troubleshooting - B-CAN System Diagnosis Test Mode B

Do this diagnosis if any of the control units are not communicating (Not Available is displayed in the HDS) as found by the B-CAN System Diagnosis Test Mode A.

1. Using the HDS, select the system that has the symptom from the BODY ELECTRICAL SYSTEM SELECT menu.
2. Select DTCs, and then check for loss of communication DTCs (use the DTC Troubleshooting to find the DTC type).

   Are any loss of communication DTCs indicated? 

   YES  - Go to step 3.

   NO  - Replace the MICU.

3. Perform the input test for the unit not communicating with the HDS.
   MICU REFERENCE
   
   

   Unit not communicating
   MICU (see MICU INPUT TEST  )
   Driver's MPCS unit (see DRIVER'S MPCS UNIT INPUT TEST  )
   Gauge control module (see GAUGE CONTROL MODULE INPUT TEST  )
   Relay control module (see RELAY CONTROL MODULE INPUT TEST  )
   Combination switch control unit (see COMBINATION SWITCH CONTROL UNIT INPUT TEST  )
   Power seat control unit (see POWER SEAT CONTROL UNIT INPUT TEST )
   HandsFreeLink control unit (see CONTROL UNIT INPUT TEST )
   Adaptive front lighting control unit (see CONTROL UNIT INPUT TEST )
   Keyless access control unit (see CONTROL UNIT INPUT TEST )
   Climate control unit (see GENERAL TROUBLESHOOTING INFORMATION )
   OnStar control unit(1) (see ONSTAR SYSTEM CONTROL UNIT INPUT TEST )
   (1) '05-06 models