Section I. TROUBLESHOOTING PROCEDURES
This section contains step-by-step procedures for identifying, locating, isolating, and repairing equipment malfunctions
by Unit maintenance personnel. This manual cannot list all malfunctions that may occur, nor all tests or inspections and
corrective actions. If a malfunction is not listed or is not corrected by the corrective actions listed, notify your supervisor.
a. Troubleshooting Format. All troubleshooting procedures are separated into left-hand and right-hand pages.
The main diagnostic logic is on the left-hand pages. Related and helpful information is on right-hand pages.
Just answer the questions on the left-hand pages. If you are not sure about a question or procedure, look on the
right-hand page for notes, instructions, and help. Follow the YES or NO path as directed to the next step.
(1) Left-Hand Pages. All critical information for decision making is found on left-hand pages. Related and
helpful information, if needed, can be found on the accompanying right-hand page. Each left-hand page
contains the following information:
(a) INITIAL SETUP -- This box is located only before the first step in a given troubleshooting fault.
INITIAL SETUP lists tools, materials, references, personnel, and equipment needed to troubleshoot the
(b) QUESTION -- Each question, located in the middle column, refers to POSSIBLE PROBLEMS. Just
answer the question YES or NO and follow the appropriate path to the next step. Everything else on
both pages is information to support the question.
(c) KNOWN INFO -- This box contains known information about the vehicle or subsystem. As you
follow a test chain, parts will be listed here after they have been found to be OK. Sometimes this box
will indicate a fault known to exist, such as "No Transit Light on All the Time." DO NOT USE THIS
BOX TO PICK A "JUMP IN" POINT. Always run a complete chain when instructed to do so.
(d) POSSIBLE PROBLEMS -- This box is the opposite of KNOWN INFO. Whatever might be causing
the problem is listed here until it is tested and shown to be OK.
(e) TEST OPTIONS -- This box lists at least one way of getting to the answer to the question. When
there is more than one way to get to the answer, all the different options will be given. The easiest or
best option is listed first.
(f) REASON FOR QUESTION -- If you know why the question is being asked, it should be easier to
understand the diagnostic logic and easier to answer the question. Many times, an explanation of how
the system or circuit works is included here. Knowing why the question is being asked should help you
decide if the answer should be YES or NO.
(2) Right-Hand Pages. Right-hand pages contain additional information. Each right-hand page contains the
(a) WARNINGs AND CAUTIONs -- Warning and caution statements are placed on the right-hand page.