DTC U0001-87: Control Module Communication Bus "B" Off - Missing message: Action
- Using the manufacturer approved diagnostic system, perform a CAN network integrity test. Refer to the appropriate system wiring diagrams and test the private high speed CAN bus circuit for short circuit to ground, short circuit to power, open circuit, high resistance
- Refer to the appropriate system wiring diagrams and test the telephone interface module power and ground circuits for open circuit, high resistance