Case IH 17660 (F-518407-04) - ECU – Bosch MD1CE101 ECM: ECM 12/24 volt actuator supply 9 is shorted to ground

The engine computer detects a short circuit to ground on the power supply line (Actuator Supply 9) feeding the DEF pump motor or the DEF reverting valve. This will disable the DEF dosing system and eventually lead to an engine derate.

• VESTRUM CVX
• Farmall 40-50 CVT
• Farmall 90X
• Farmall 100A series
• Vestrum 100-130 CVX
• Maxxum
• Puma
• Optum
• Magnum
• Steiger
• Quadtrac
• Axial-Flow 7240
• Axial-Flow 8240

1. 1

   Visually inspect the wiring harness running from the MD1CE101 ECU to the DEF/SCR Dosing Pump module for chafed, melted, or pinched wires shorting against the machine's frame or exhaust components.

2. 2

   Disconnect Connector 3 (Code G, 48-pin) at the ECU. Inspect pins 1.05 and 1.08 for corrosion, bent pins, or moisture intrusion.

3. 3

   Disconnect the electrical connector at the SCR DEF Pump / Reverting Valve module. Check for continuity to ground on the harness side of pins 1.05 and 1.08. If the short to ground disappears when the pump is unplugged, the SCR pump motor or reverting valve is internally shorted. If the short to ground remains with the pump unplugged, the wiring harness itself is shorted to the chassis.

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery cable.

2. 2

   Harness Repair

   If the diagnostic checks revealed a harness short, locate the chafed section of the wire. Cut out the damaged section, splice in new wire using weather-sealed heat-shrink butt connectors, and re-loom the harness securely away from vibration points.

3. 3

   Component Replacement

   If the SCR Reverting Valve or Pump Motor is internally shorted, the DEF Dosing Pump Module assembly must be replaced. Drain the DEF fluid from the lines, disconnect the fluid lines and electrical connectors, unbolt the faulty module, install the new module and torque to OEM spec, then reconnect the lines and connectors.

4. 4

   Clear and Test

   Reconnect the battery. Use the Case IH Electronic Service Tool (EST) to clear the 17660 fault code. Run an SCR system test/dosing override via the EST to prime the pump, check for leaks, and verify the short-to-ground condition has been resolved.