This article explains why the event message

appears in the syslog.


is logged when the chassis process (chassisd) cannot read back information from the I2C slave (I2CS) about the indicated component (field-replaceable unit, or FRU).

Below are the symptoms for two example scenarios.

Example 1

Example 1 was due to the ribbon cable on the FPM (Front Panel Board) being improperly seated. Reseating the ribbon cable fixed the issue.

Example 2

Example 2 was caused by a bad Control Board in slot 0 that had to be replaced.

The I2C master initiates all communication on the I2C bus and supplies the clock for all slave devices. If there is an issue with the I2C slave, it disrupts communication with the I2C bus and the device ID. Data is disrupted on the FRU component and does not populate the show chassis hardware detail command output. The chassisd will identify the failed FRU component in the log messages. The failed FRU component will appear in the text following the


For example, in the following message, Control Board slot 0 is identified as the problem FRU component:

The most probable cause for the

is a hardware error.

Perform these steps to determine the cause and resolve the problem (if any). Continue through each step until the problem is resolved.

1. Collect the show command output.

Capture the output to a file (in case you have to open a technical support case). To do this, configure each SSH client/terminal emulator to log your session.

2. Analyze the show command output.

  • There are many different hardware components on the chassis; for detailed information about the output of many possible show commands, see the Ethernet Interfaces Feature Guide for Routing Devices.
  • After you have identified the device that is the problem, try reseating the device. After the device is pulled, check for bent pins on the chassis slot and for burn marks where the pins meet the device.

Note: On MX Series routers, the FPM (Front Panel Board) is connected via a ribbon cable between the chassis and the FPM. The ribbon cable may need to be reseated at the chassis as well as the FPM board.


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