TM-9-2320-272-23-2
TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)
TECHNICAL MANUAL; FIELD MAINTENANCE MANUAL; VOLUME 2 OF 5
SEPTEMBER 2012
TM-9-2320-272-23-2 - Page 307 of 1417
NG80: STARTER CIRCUIT TESTS - Continued
STEP
1.
Setup test equipment.
a.
M939/A1.
NOTE
Current probe should be at least 10 in. (24.5 cm) from alternator.
(1)
Install current probe on positive starter cable connected to starter. Point arrow on probe toward
starter.
(2)
Ensure current probe is closed.
(3)
Try to crank engine for several cycles with fuel shutoff.
(4)
Unclamp current probe from battery cable.
b.
M939A2.
(1)
Install current probe around output wire on alternator.
(2)
Point arrow on probe away from alternator.
2.
Do current probe offset.
a.
Turn off all vehicle electrical power.
b.
Dial 74 into TEST SELECT.
Table
1.
Starter Circuit Resistance Test.
Test NO.
Test
74
Starter Circuit Resistance
c.
Press and hold TEST until CAL message appears on the display.
T0019DAA
Figure 1.
CAL Message.
d.
Release TEST.
e.
Wait for offset value to appear.
CONDITION/INDICATION
Is offset value within limits of -225 to +225?
DECISION
YES - Go to Step (3).
NO - Proceed to TM 9-4910-571-12&P for offset fault isolation.
TM 9-2320-272-23-2
0202
0202-2
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