TM-9-2320-272-10

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; OPERATOR'S MANUAL

SEPTEMBER 2004

CHANGE 2

TM-9-2320-272-10 - Page 105 of 481

TM 9-2320-272-10

2-6

2-3. CHASSIS CONTROLS AND INDICATORS (Contd)

Key

Item and Function

1

SELECTOR PANEL (M939A2 series vehicles) contains selectors for the four

preset tire pressure modes and a run-flat selector.

2

AMBER WARNING LIGHT (M939A2 series vehicles) flashes as an overspeed

warning for cross-country and sand tire pressure modes. It will stay lit when the

emergency tire pressure mode is selected.

3

RUN FLAT (M939A2 series vehicles) selector causes the CTIS to check tire

pressures every fifteen seconds.

4

ELECTRONIC CONTROL UNIT (ECU) (M9393A2 series vehicles) is the

microprocessor in the CTIS. It is contained in the selector panel housing.

5

EMERGENCY (EMER) (M939A2 series vehicles) tire pressure selector is used for

operating the vehicle in extreme terrain conditions where maximum traction is

required.

6

SAND (M939A2 series vehicles) tire pressure selector is used for operating the

vehicle in sand, snow, and mud.

7

CROSS-COUNTRY (X-C) (M939A2 series vehicles) tire pressure selector is used

for operating the vehicle on non-paved secondary roads and unimproved surfaces.

8

HIGHWAY (HWY) (M939A2 series vehicles) tire pressure selector is the normal

operating modes of CTIS. The highway mode is automatically set each time the

engine is started.