This article explains the meaning of the "offline_reason = Bad Voltage" alarm that is seen on MX Series routers and indicates if any action needs to be taken.

The following log messages are seen on the Flexible PIC Concentrator (FPC):

Chassisd: 

Aug 2 05:29:54 atlas_i2cs_power_ok: FPC-4 Power Up State 0x00000020

Aug 2 05:29:54 atlas_i2cs_power_ok: FPC-4 Power Disable Cause 0x00000040

Aug 2 05:29:54 atlas_i2cs_power_ok: FPC-4 Power VFail 1 Cause 0x00000040

Aug 2 05:29:54 atlas_i2cs_power_ok: FPC-4 Power VFail 2 Cause 0x00000000

Aug 2 05:29:56 rcv: ch_ipc_dispatch() ipc pipe read error for args 0xa22d920 pipe 0x97fd7c0, fru FPC 4 subfru 0 errno 60

Aug 2 05:29:56 ch_ipc_dispatch: fru FPC offline_reason = Bad Voltage

Aug 2 05:29:56 ch_connection_shutdown: Destroying the IPC pipe

Aug 2 05:29:56 fpc_disconnect_generic: fpc 4 slc 0 state Online cargs 0xa22d920 clean_shutdown 0, offline_reason=Bad Voltage

Aug 2 05:29:56 -- FPC 4, last request 132, state Online

Aug 2 05:29:56 -- PWR_VFAIL_CAUSE     0x40 STMX_PWR_EN_PCIE_0V9_R

Aug 2 05:29:56 CHASSISD_IPC_CONNECTION_DROPPED: Dropped IPC connection for FPC 4

•  STMX_PWR_EN_PCIE_0V9_R in PWR_VFAIL_CAUSE suggests a power supply failure related to the 0.9V rail, indicating a potential issue with enabling or providing power to that particular voltage rail in the device.
•  It is referring to voltage rail failure on the ASIC.
• This is usually a hardware issue. 
• We can try to physically reseat the FPC.
• In case physical reseat doesn't help, need to proceed with hardware replacement.