TM 1-2840-252-23-3
G-64
NO OBSERVED ENGINE SPEED REDUCTION DURING OVERSPEED TEST EXPANDED INSTRUCTIONS.
Step 2.
Check harness connectors PL1 AND PL3 (figure 201) at DECU, and P9 at overspeed solenoid for tight
connection.
Step 3.
Disconnect connectors PL1, PL3 and P9 to check pins and sockets.
Step 5.
With PL1 disconnected and overspeed test not selected, check resistance of overspeed switch at
harness PL1 connector sockets A and B (figure 202). Limit is > 50K . With overspeed test selected.
1
check resistance again. Limit is <50 .
Step 6.
With PL3 disconnected, check resistance of overspeed solenoid at harness PL3 connector sockets P and
R (figure 202). Limit is 15.0 - 55.0 .
Step 7.
With PL3 disconnected at both DECUs, check the resistance between the DECUs at the following
harness PL3 sockets:
DECU #1
DECU #2
g
Y
Y
g
Limit in each case is <1 .
Step 8.
Before tightening harness connectors PL1, PL3 and P9, be sure that keyways in harness connectors are
aligned with keyways in component connectors.
Step 12.
With P9 disconnected, check resistance of overspeed solenoid at solenoid J9 connector pins A and B.
Limit is 15.0 - 55.0 .
Step 14.
Refer to manufacturer's procedure for checking overspeed valve operation.
Step 17.
Refer to manufacturer's procedure for diagnosing and replacing harness or overspeed solenoid.
Step 19.
Refer to manufacturer's procedure for diagnosing and replacing harness or switch.
Step 21.
Refer to manufacturer's procedure for diagnosing and replacing harness.
Step 22.
Refer to manufacturer's procedure for diagnosing and replacing overspeed solenoid.
Step 24.
Refer to manufacturer's procedure for diagnosing and replacing harness.
Step 25.
Refer to manufacturer's procedure for diagnosing and replacing overspeed valv .
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G-149
