The CMODs have an internal test circuit that you can use to locate failed DIMMs and verify a failed CPU after removing the CMOD from the server. The DIMM and CPU Fault Remind circuits hold an electrical charge for 10 minutes after power is removed from the server, allowing enough time to remove the CMOD and use the circuit.
For more information, see Replace a Failed DIMM and Remove a Heatsink and Processor (FRU).