Propulsion System; Machine Moves Neither Forward Nor Backward 1/2 - Sakai R2-4 Shop Manual

2-4. Propulsion System

Check following items before troubleshooting.
• No blown fuses and power is applied up to fuses.
• when measuring voltage and current without disconnecting connectors, refer to "Measuring voltage and current
flowing using tester" (P.10-006 to P.10-008).
• Check any ground circuit which belongs to components to be checked.

2-4-1. Machine moves neither forward nor backward 1/2

• Parking brake switch must be released.
• Foot brake switch must be ON (Brake pedal is not depressed).
Reference Fig.: 2-4-1
Check point
1. Parking Brake Solenoid
2. Propulsion Pump
Neutral Solenoid
3. Brake Relay
4. Foot Brake Switch
5. Parking Brake Switch
Check/Cause
• Disconnect harness and measure resistance of coil.
Standard resistance : 8.5 Ω
• If measured resistance is abnormal, parking brake
solenoid is faulty.
• Disconnect harness and measure resistance of coil.
Standard resistance : 8.5 Ω
• If measured resistance is abnormal, propulsion pump
neutral solenoid is faulty.
(1) when starter switch is ON, measure voltage between
brake relay terminal 1 inlet wire BW and chassis
ground.
Standard voltage : 12 V or more
(2) when starter switch is ON, measure voltage between
brake relay terminal 3 inlet wire GW and chassis
ground.
Standard voltage : 12 V or more
(3) when starter switch is ON, measure voltage between
brake relay terminal 5 outlet wire BrB and chassis
ground.
Standard voltage : 12 V or more
• If above items (1) and (2) are OK and item (3) is NG,
brake relay is faulty.
(1) when starter switch is ON, measure voltage between
foot brake switch terminal COM inlet wire wB and
chassis ground.
Standard voltage : 12 V or more
(2) when starter switch is ON, measure voltage between
foot brake switch terminal NO outlet wire Bw and
chassis ground.
Standard voltage : 12 V or more
• If above item (1) is OK and item (2) is NG, foot brake
switch is faulty.
(1) when starter switch is ON, measure voltage between
parking brake switch terminal 1 inlet wire WB and
chassis ground.
Standard voltage : 12 V or more
(2) when starter switch is ON, measure voltage between
parking brake switch terminal 3 outlet wire GW and
chassis ground.
Standard voltage : 12 V or more
• If above item (1) is OK and item (2) is NG, parking brake
switch is faulty.
TROUBLESHOOTING
Action
Replace parking brake
solenoid.
Replace propulsion
pump neutral solenoid.
Replace brake relay.
Replace foot brake
switch.
Replace parking brake
switch.
10-029