What this code means

1: start-up test. Before switching the LC on, the software checks the power bridge: it turns on alternatingly the High side Power Mosfets and expects the phases voltage to increase toward the rail capacitor value. If the phases voltage does not increase, this alarm occurs. Cause 2: Motor running test. When the motor is running, power bridge is ON, the motor voltage feedback is tested; if it is lower than commanded value, fault status is entered.

Applies to: ZAPI ACE0 / COMBIAC0 controller.

Possible causes / checks (from the source)

A) If the problem occurs at start up (the LC does not close at all), check: - Motor internal connections (ohmic continuity) - Motor power cables connections - Motor leakage to truck frame - If the motor connections are OK, the problem is inside the controller B) If the alarm occurs during motor running, check: - Motor connections - If motor phases windings/cables have leakages towards truck frame - That the LC power contact closer properly, with a good contact - If no problem are found on the motors, the problem is inside the controller.

Need the part?

If diagnosis points to a failed sensor, solenoid, controller or harness part, send us the code (VMN LOW), machine model and serial number — we quote genuine and OEM replacement parts for export.