4-25
TRBL
SHTG
Troubleshooting
Troubleshooting the PTT unit
Troubleshooting consists of the following 3 items:
Symptom 1: Specific trouble conditions
Symptom 2: Trouble conditions of an area or individual part
Cause: Trouble causes of symptom 2
— : Not applicable
Symptom 1: PTT unit does not operate.
Symptom 2 Cause Checking step
See
page
PTT relay does not
operate
Blown fuse (PTT switch) Check the fuse. 5-3
A-11
PTT switch malfunction Check the PTT switch. 5-75
PTT relay malfunction Check the PTT relay. 5-74
Short, open, or loose
connection of the wiring
harness
Measure the PTT switch input voltage. 5-75
Measure the PTT relay input voltage. 5-74
Check for continuity between the PTT
switch and the fuse holder.
5-75
A-11
Check for continuity between the PTT
switch and PTT relay.
5-75
A-11
PTT motor does not
operate
PTT motor malfunction Disassemble and check the PTT
motor.
9-45
Short, open, or loose
connection in PTT motor
circuit
Check for wiring continuity between
the PTT motor and the PTT relay
terminal.
A-11
PTT fluid pressure
does not increase
— Measure the PTT fluid pressure. 9-38
Manual valve open Check the manual valve. 9-40
Insufficient PTT fluid Add sufficient PTT fluid. 10-14
PTT fluid leakage Check the PTT fluid leakage. 10-15
Air in PTT Bleed the PTT unit. 9-40
Clogged fluid passage Disassemble and check the PTT unit. 9-50
9-56
Check the filter for dirt and
obstructions.
9-53
Check the valves for damage. 9-53
Check the fluid passages for
obstructions.
9-50
9-56
Gear pump malfunction Check the gear pump operation. 9-53