Yale 523920-4 – VSM: REV Circuit Shorted Low

This fault code indicates a problem with the reverse circuit in the powershift transmission system. It is triggered when the VSM detects that the reverse coil driver output is shorted to ground, there is an open circuit in the coil or wiring harness, or there is an internal functional failure within the controller itself.

• Yale and Hyster Forklifts
• Yale Veracitor VX
• Yale GLC
• Yale GLP
• Yale GDP
• Hyster FT
• Hyster S80FT
• Hyster H60FT

1. 1

   Power cycle the forklift (OFF for at least 30 seconds, then ON) to see if the DTC clears or reoccurs.

2. 2

   Visually inspect all connectors and the wiring harness associated with the reverse transmission solenoid valve for damaged wires, loose connections, or corrosion.

3. 3

   With truck power OFF and connectors disconnected, use a Digital Multimeter to measure resistance between the VSM connector (+) and battery negative (-). A reading under 0.5 ohms indicates a short to ground.

1. 1

   Repair or replace wiring harness

   If the resistance test shows less than 0.5 ohms, locate the shorted wire or connection between the VSM and the reverse solenoid valve. Repair or replace the damaged harness section.

2. 2

   Replace reverse transmission solenoid valve

   If the wiring harness is intact and no short is found, the issue is likely an open circuit inside the coil. Replace the reverse transmission solenoid valve/coil.

3. 3

   Replace and calibrate VSM

   If the harness and solenoid valve both test normal, the VSM has suffered a functional failure. Replace the VSM and calibrate/program it to the specific forklift.