When to Replace the BCM

Replace the BCM only if diagnostics in this section specifically direct you. Most system problems are traceable to faulty wiring, to connectors, or to components. The BCM itself is very reliable and is not likely the cause of a fault. Do NOT replace the BCM before performing a complete diagnosis or recurrence of the fault will likely occur. Note: Every input to the BCM is short to ground and short to battery protected. Every output from the BCM is short to ground and short to battery protected. Therefore, the BCM does not automatically need to be replaced when a short is found in the wiring connected to the BCM. Repair the wiring first, then test the system for any further problem.