TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 2/TASK 1
The VTM will now
display the rpm and the oil pressure
Now he starts
the vehicle engine and holds the engine
speed at 2000 rpm. SGT Reed
observes the VTM display for correct oil
pressure. The indicated oil
pressure should be between 40 psi and 70
Since the oil pressure is not within these limits, SGT Reed is
directed to stop the engine IMMEDIATELY and use LO 9-2320-280-12 to
check the type of oil used in the vehicle and to replace the oil
filter. The procedures for replacing the oil filter can be found in
paragraph 3-5, page 3-6 of the TM. Once the necessary repairs have
been made, SGT Reed reruns the Go Chain test to ensure that the
malfunction has been corrected and that no additional problems exist.
(3) No-Go Test 81. For these test procedures, we will follow SSG
Boyce as he performs the test procedures that lead us to the
conclusion that the batteries need to be replaced.
Step 1. Install Test Probe Cable W2-Do Offset Test. SSG Boyce first
disconnects the fuel solenoid lead 54A. He then connects test probe
cable W2 to jack J4 on the VTM and shorts the red and black leads
together. He now dials 89 into the TEST SELECT switches and presses
and holds the TEST button until the CAL message appears on the
display. The offset value should be between -6.8 to +6.8. Since the
reading received was well within these limits, SSG Boyce connects the
red lead to the positive post of the terminal being tested and the
black lead to the negative post of the terminal being tested.
Step 2. Condition Current Probe-Do Offset. SSG Boyce connects plug
P1 of the transducer cable W4 to jack J3 on the VTM.
connects plug P2 of the transducer cable W4 to the current probe.
Now he clamps the current probe around the battery cable which
connects the series pair of batteries containing the battery being
Point the arrow on the current probe toward the negative
post connected to the battery cable.
He now attempts to crank the
engine for several cycles.
SSG Boyce now turns off all vehicle electrical power and dials 90
into the TEST SELECT switches. He presses and holds the TEST button
until the prompting message CAL appears on the display. Once