TM-9-2320-272-24-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4
JUNE 1998
TM-9-2320-272-24-1 - Page 149 of 1015
TM 9-2320-272-24-1
2-20. UNIT TROUBLESHOOTING INDEX
PARA.
TITLE
PAGE
NO.
NO.
2-21.
Mechanical Troubleshooting
2-61
2-22.
Electrical System Troubleshooting
2-92
2-23.
Compressed Air and Brake System Troubleshooting
2-177
2-24.
STE/ICE Troubleshooting
2-219
2-25.
Central Tire Inflation System (CTIS) Troubleshooting
2-267
2-21. MECHANICAL TROUBLESHOOTING
NOTE
If malfunction corrective action does not correct malfunction,
notify direct support maintenance.
a.
This section provides information to diagnose and correct malfunctions of the mechanical system at
the unit maintenance level.
b.
This section cannot list all mechanical malfunctions that may occur. If a malfunction occurs that is
not listed in table 2-2, notify direct support maintenance.
MECHANICAL TROUBLESHOOTING SYMPTOM INDEX
MALFUNCTION
NO.
MALFUNCTION
TROUBLESHOOTING
PROCEDURE
PAGE
1.
2.
3.
4.
5.
6.
7.
8.
9:
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
ENGINE
Engine will not crank
........................................
Engine cranks but will not start.
...............................
Starter cranks engine slowly, hard to start.
.......................
Engine stops during normal operation
...........................
Engine stops when accelerator is returned to idle position
...........
Engine fails to stop
..........................................
Engine misfires during operation
...............................
Engine idle rough, erratic (M939A2 only).
........................
Poor acceleration and/or lack of power
...........................
Enginesurges .
.............................................
Excessive engine oil loss or consumption
.........................
Engine oil pressure too low or too high at normal operating temperature
Engine oil contaminated
......................................
Excessive vibrating or clunking
................................
Excessive fuel consumption.
...................................
ETHER START SYSTEM
Engine cranks but will not start in cold weather
(fuel system operating properly)
...............................
EXHAUST SYSTEM
Exhaust color blue during normal operation
......................
Exhaust color white during normal operation and idle
..............
Exhaust color black during normal operation and idle.
..............
Excessive exhaust noise
......................................
Exhaust fumes in cab
........................................
2-64
2-64
2-66
2-66
2-66
2-66
2-67
2-67
2-67
2-68
2-68
2-69
2-70
2-70
2-70
2-71
2-71
2-72
2-72
2-72
2-73
2-61
Back to Top
