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Error LEDs

This section describes the Error LEDs on the system board and the suggested actions to correct the detected problems.

The illustration shows the system-board LEDs. The system board has error LEDs that will help to locate the source of the error. Run the diagnostic programs to find out the cause of the error (see Dynamic System Analysis).

Figure 1. LED location on system board
LED location on system board

The server is designed so that LEDs remain lit when the server is connected to an ac power source but is not turned on, provided that the power supply is operating correctly. This feature helps you to isolate the problem when the operating system is shut down.

Note
When you disconnect the power source from the server, you lose the ability to view the LEDs because the LEDs are not lit when the power source is removed. Before you disconnect the power source, make a note of which LEDs are lit, including the LEDs that are lit on the operation information panel and LEDs inside the server on the system board.

Many errors are first indicated by a lit system-error LED on the control-panel assembly of the server. If this LED is lit, one or more LEDs elsewhere in the server might also be lit and can direct you to the source of the error.

Before you work inside the server to view the LEDs, read the Safety and Handling static-sensitive devices.

If an error occurs, view the server LEDs in the following order:
  1. Check the control-panel assembly on the front of the server. If the system-error LED is lit, it indicates that an error has occurred.
  2. Check the front and rear of the server to determine whether any component LEDs are lit.
  3. Remove the server top cover and look inside the server for lit LEDs. Certain components inside the server have LEDs that will be lit to indicate the location of a problem. For example, a DIMM error will light the LED next to the failing DIMM on the system board.
  4. Look at the system service label inside the top cover of the server, which gives an overview of internal components. This information can often provide enough information to correct the error.
The following table describes the LEDs on the system board and suggested actions to correct the detected problems.
Table 1. Suggested actions to correct the detected problem for each LED light.

Three column table for documenting the LED, description, and action.

  • Follow the suggested actions in the order in which they are listed in the Action column until the problem is solved.
  • If an action step is preceded by (Trained technician only), that step must be performed only by a trained technician.
  • Go to the Lenovo support website at the Lenovo Support Portal to check for technical information, hints, tips, and new device drivers or to submit a request for information.
LEDDescriptionAction
DIMM error LEDsA memory DIMM has failed or is incorrectly installed.
  1. Remove the DIMM that has the lit error LED.
  2. Reseat the DIMM.
  3. Replace the following components one at a time, in the order shown, restarting the server each time:
    1. DIMM
    2. (Trained technician only) System board
Microprocessor error LEDMicroprocessor has failed, is missing, or has been incorrectly installed.
Note
(Trained service technician only) Make sure that the microprocessor is installed in the correct sequence; see Replacing the microprocessor and heat sink.
  1. Check the system-event log to determine the reason for the lit LED.
  2. (Trained technician only) Reseat the failing microprocessor.
  3. Replace the following components one at a time, in the order shown, restarting the server each time:
    1. (Trained technician only) Failing microprocessor
    2. (Trained technician only) System board
System-board error LEDSystem-board CPU VRD and/or power voltage regulators have failed.(Trained technician only) Replace the system board.
IMM2 heartbeat LED

Indicates the status of the boot process of the IMM2.

When the server is connected to power this LED flashes quickly to indicate that the IMM2 code is loading. When the loading is complete, the LED stops flashing briefly and then flashes slowly to indicate that the IMM2 if fully operational and you can press the power-control button to start the server.

If the LED does not begin flashing within 30 seconds of when the server is connected to power, complete the following steps:
  1. (Trained technician only) Recover the firmware (see Recovering the server firmware (UEFI update failure)).
  2. (Trained technician only) Replace the system board.
RTMM heartbeat LEDPower-on and power-off sequencing.
  1. If the LED flashes at 1Hz, it is functioning properly and no action is necessary.
  2. (Trained technician only) If the LED is not flashing, replace the system board.