TM-9-2320-272-23-1
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 1 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-1 - Page 275 of 1313
GENERAL TROUBLESHOOTING INDEX - Continued
Malfunction/Symptom
Troubleshooting Procedure
8.
Warning Buzzer Sounds When Brakes Are Applied (Primary
And Secondary Gauge Pressure Drops Below 55-65 psi
(379-448 kPa)).
.................................................................................................................................
WP
0125
9.
No Air Pressure (Warning Buzzer Sounding, Air Pressure Not
Building To Normal Operating Range As Indicated By Gauges).
......................................................
WP
0126
10.
Air Pressure Does Not Build To Normal Operating Pressure
(Above 80 psi (552 kPa)) According To Gauges.
..............................................................................
WP
0127
11.
Air Pressure Builds Slowly (Takes Excessive Amount Of Time
To Build To 100 psi (690kPa)).
.........................................................................................................
WP
0128
12.
Air Pressure Exceeds Maximum (Gauges Show Over 130 psi
(896 kPa)), Safety Valve Opens To Release Pressure.
....................................................................
WP
0129
13.
Primary Pressure Gauge Reads No Pressure, Low Pressure,
Or Builds To Normal Operating Pressure Slowly. Secondary
Pressure Gauge Reads Normal (Engine Idling, Brake Pedal Not
Applied).
............................................................................................................................................
WP
0130
14.
Secondary Pressure Gauge Reads No Pressure, Low
Pressure, Or Builds To Normal Operating Pressure Slowly.
Primary Pressure Gauge Reads Normal (Engine Idling, Brake
Pedal Not Applied).
...........................................................................................................................
WP
0131
15.
Primary Air System Fails To Maintain Pressure (No Major
Leaks, Air Can Be Heard Escaping Into Air Intake Stack,
Parking Brake Applied).
....................................................................................................................
WP
0132
16.
Secondary Air System Fails To Maintain Pressure (No Major
Leaks, Air Can Be Heard Escaping Into Air Intake Stack,
Parking Brake Applied).
....................................................................................................................
WP
0133
17.
Warning Buzzer Fails To Sound Or Fails To Shut Off On Low
Pressure (below 55-65 psi (379-448 kPa)), Air Pressure
System Operating Normally.
.............................................................................................................
WP
0134
18.
Spring Brakes Do Not Release (Vehicle Brakes Grab Or Drag).
......................................................
WP
0135
19.
Spring Brakes Do Not Set (Gauges At Normal Operating
Pressures, Air Exhausting Not Heard When Parking Brake
Applied).
............................................................................................................................................
WP
0136
20.
All Air-Operated Accessories Do Not Operate (Horn,
Windshield Wipers, Windshield Washers, Transfer Case
Controls), Gauges At Normal Operating Pressure.
...........................................................................
WP
0137
21.
Cooling Fan Does Not Operate, Engine Temperature Above
200°F (93°C) As Indicated By Temperature Gauge.
.........................................................................
WP
0138
22.
Cooling Fan Does Not Stop Running, Engine Temperature
Below Normal Operating Range (Override Bolt Not Installed).
.........................................................
WP
0139
23.
Front Wheel Drive Does Not Engage (Front Wheel Drive Lock-
In Switch Engaged And Transfer Case Shift Lever In HIGH
Position).
...........................................................................................................................................
WP
0140
TM 9-2320-272-23-1
0005
0005-6
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