Diagnostic Codes, Beep Codes, and Error Messages 3-1
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This chapter describes diagnostic and beep codes and system error messages 
that can occur during system start-up or, in the case of some failures, during 
normal system operation. In some cases, the system may display error mes-
sages and emit beep codes simultaneously or may display a diagnostic code 
and will not boot. In other cases, such as when a video problem occurs, the 
system may emit a beep code even though it cannot display an error message.
If a faulty system does not emit diagnostic or beep codes or display system 
error messages to indicate a failure, run the appropriate tests in the diskette-
based diagnostics to help you isolate the source of the problem. For instruc-
tions on starting and using the diskette-based diagnostics, see “Running the 
Dell Diagnostics” in Chapter 2.
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Your system is equipped with four diagnostic code indicators, which are 
labeled “A,” “B,” “C,” and “D” on the back of the computer. Each of the four 
indicators can be yellow or green. When the computer is turned on or 
restarted and the system is functioning normally, the indicators flash during 
POST. After the system boots, the indicators remain green to signify normal 
system operation.
If a malfunction is detected and the computer fails to boot, the indicators dis-
play a code that identifies the problem. In this situation, write down the 
diagnostic code displayed and look it up in Table 3-1.