John Deere 2646.03 – SCO: Stepper Motors for E-SCV XI and E-SCV XIV, Voltage Too High

The system has detected that the voltage on the driver circuit for the rear Selective Control Valve (SCV) 14 stepper motor is too high. This typically indicates a short to a 12-volt power source in the wiring, or an internal short within the stepper motor or the control module itself.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 8245R
• 8270R
• 8295R
• 8320R
• 8335R
• 8345R
• 8370R
• 8400R
• 7210R
• 7230R
• 7250R
• 7270R
• 7290R
• 7310R

1. 1

   Inspect the wiring harness between the SCO (Front Chassis Module) and the E-SCV XIV stepper motor for rubbed, melted, or pinched wires causing a short to a 12V power source.

2. 2

   Inspect electrical connectors at both the SCV stepper motor and the SCO module for corrosion, moisture, looseness, or bent pins.

3. 3

   Ensure the power supply to the SCV components is stable and within the required voltage range.

4. 4

   Disconnect the E-SCV XIV stepper motor to isolate the component. If the high voltage code changes to a low voltage/open circuit code (SCO 002646.04), the wiring is intact and the short is internal to the stepper motor.

1. 1

   Power Down

   Turn off the machine and disconnect the battery to prevent electrical spikes during the repair.

2. 2

   Wiring Repair

   If the diagnostic checks revealed a short to power in the harness, repair the damaged wire(s) or replace the affected harness section. Clean and secure all connections.

3. 3

   Replace the Stepper Motor

   If the wiring tests good, the E-SCV XIV stepper motor has an internal short. Unbolt the faulty stepper motor from the rear SCV block and install the replacement unit.

4. 4

   Module Replacement (Worst Case)

   If replacing the stepper motor and verifying the wiring does not clear the high-voltage condition, the SCO (Front Chassis Module) itself may have an internal failure on that specific driver circuit and will need to be replaced and reprogrammed by a dealer.

5. 5

   Reassemble and Test

   Reconnect the battery, clear the stored SCO fault codes, and actuate the SCV 14 valve to ensure normal operation without the code returning.