What does Kobelco fault code M01-A03 mean?

Q: What does Kobelco fault code M01-A03 mean?

M01-A03 indicates: Hoist-up function cut off; Continuous alarm; LMI indicates "Two-Block." Fix: Anti-Two Block (ATB) Circuit Open. LOGIC: The M01 controller monitors a constant closed loop (usually 24V or a 1k-ohm resistor signal). An interruption in this loop triggers the safety lockout. ACTION: 1. Verify the ATB weight isn't physically lifting the switch. 2. Check for "Green Crusties" in the boom-tip junction box. 3. Ohm-test the reeling cable. FIX: Replace broken reeling cable; replace the limit switch; or repair the ground connection at the boom foot.

Kobelco Fault Code

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M01-A03

Hoist-up function cut off; Continuous alarm; LMI indicates "Two-Block."

System

Not specified

Symptom

Hoist-up function cut off; Continuous alarm; LMI indicates "Two-Block."

Diagnosis & fix steps

Anti-Two Block (ATB) Circuit Open. LOGIC: The M01 controller monitors a constant closed loop (usually 24V or a 1k-ohm resistor signal). An interruption in this loop triggers the safety lockout. ACTION: 1. Verify the ATB weight isn't physically lifting the switch. 2. Check for "Green Crusties" in the boom-tip junction box. 3. Ohm-test the reeling cable. FIX: Replace broken reeling cable; replace the limit switch; or repair the ground connection at the boom foot.

Red Seal field insights

The 10-Ohm Rule: If you use a multimeter at the boom base, you should see very low resistance (near 0-10 ohms) through the circuit. If you see "OL" (Open Loop), the wire is snapped inside the insulation of the reeling cable. This often happens if the cable was over-tensioned during boom extension.

Same code keeps coming back?

That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.

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Read before you touch anything

This is general reference information, not a repair manual. It is for trained, qualified technicians.
Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.

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