John Deere 523937.05 – SCO / ACU: SCV 6 Circuit Current Below Normal

The fault code indicates an electrical issue with the circuit for the number 6 Selective Control Valve (SCV). The FMI .05 signifies a 'current below normal' condition, which typically points to an open circuit, high resistance in the wiring or connector, or a faulty solenoid on the SCV. This affects the tractor's hydraulic control system managed by the Secondary Hydraulic Control Unit (SCO) or Armrest Control Unit (ACU).

• 6R
• 7R
• 8R
• 9R

1. 1

   Visually inspect the wiring harness and connectors leading to the SCV 6 solenoid for pinched, chafed, or frayed wires, and ensure connectors are clean and securely fastened

2. 2

   Check the area around the batteries and alternator for accumulated debris that could cause electrical issues

3. 3

   Ensure the operator seat switch is functioning correctly, as operator presence can trigger SCV-related faults

4. 4

   Recycle power by shutting down the tractor, waiting a few moments, and restarting to see if the fault code clears

5. 5

   Inspect fuses related to the hydraulic control units for any blown fuses that could interrupt power to the SCV circuits

1. 1

   Test the solenoid

   Using a multimeter, measure the resistance of the SCV 6 solenoid. An out-of-specification or infinite resistance reading indicates a faulty solenoid coil that needs to be replaced.

2. 2

   Inspect wiring and connectors

   If the solenoid tests within specifications, disconnect the harness from both the control unit and the SCV 6 solenoid. Check for continuity on each wire to identify any open circuits. Inspect the connector pins for corrosion or damage causing high resistance.

3. 3

   Check for voltage

   With the key on and the SCV commanded, carefully check for voltage at the solenoid connector. A lack of voltage points to a problem upstream in the wiring or the control unit itself.

4. 4

   Component substitution

   If available, swap the suspected faulty solenoid with a known good solenoid from another SCV to quickly determine if the solenoid is the cause of the issue.

5. 5

   Control unit inspection

   If all wiring and components test correctly, the issue may be within the SCO or ACU. This should be diagnosed by a qualified John Deere technician, as it may require specialized diagnostic tools like John Deere Service ADVISOR.