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 1214 of 1313
FIELD MAINTENANCE
FIVE INDICATOR LIGHTS FLASHING
INITIAL SETUP:
Tools and Special Tools
Tool Kit, General Mechanic's: Automotive
(Volume 5, WP
0826, Table 1, Item 56)
Goggles, Industrial
(Volume 5, WP
0826, Table 1, Item 20)
Multimeter
(Volume 5, WP
0826, Table 1, Item 34)
Soap Solution
Test Set, Electronic Systems
(Volume 5, WP
0826, Table 1, Item 51)
Personnel Required
(2)
References
Point to Point Schematics
References (cont.)
WP
0006
Volume 2, WP
0322
Volume 2, WP
0324
Volume 5, WP
0813
Volume 5, WP
0810
Volume 5, WP
0812
Equipment Condition
Vehicle parked and engine shut down.
(TM
9-2320-272-10)
TROUBLESHOOTING PROCEDURE
FIVE INDICATOR LIGHTS FLASHING
NOTE
•
Conduct these malfunction tests if five indicator lights flash. This procedure will check for
a problem with air lines between quick release valves and pneumatic controller, and
between wheel and quick release valves. It will also check for a faulty hub air seal,
pneumatic controller, electrical lead on pressure switch at wet tank, CTIS wiring harness,
pressure switch, ECU and pressure transducer.
•
The ECU has a self-diagnostic capability which prevents operation of the CTIS when key
elements or components of the system malfunction. When the ECU shuts down due to
such system malfunction, the condition will be indicated by the flashing of all five mode
lights on ECU selector panel. Since it is unlikely that the CTIS would operate properly,
there is no option to override the ECU until the problem is corrected. An indication of five
flashing lights can be caused by any of four conditions: 1) Faulty air line to tires; 2) Faulty
pneumatic controller; 3) Faulty pressure switch circuit; 4) Faulty pressure transducer
circuit.
TM 9-2320-272-23-1
0146
0146-1
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