Massey Ferguson D193 – Transmission/linkage/suspended front axle controller / Autotronic 5 DC / Instrument Panel Control Unit (DCC3): Steering gear ratio quick change potentiometer

Electrical signal is too high from the steering gear ratio quick change potentiometer (Component X144), typically indicating a short to power or an open circuit on the ground side.

• MF 8600
• MF 8650
• MF 8660
• MF 8670
• MF 8680
• MF 8690
• MF 8450
• MF 8460
• MF 8470
• MF 8480
• 8600 Series
• 8650
• 8660
• 8670
• 8680
• 8690
• 7600 Series
• 6700 S Series
• 5700 S Series
• 5700 SL Series
• 5400 Series
• 5S Series

1. 1

   Verify the D193 code is active in the Instrument Panel Control Unit

2. 2

   Inspect the wiring harness leading to the X144 potentiometer for rubbed wires causing a short to a 12V/5V power source

3. 3

   Check for a broken or corroded ground wire (open circuit) that would cause the signal voltage to max out

4. 4

   Ensure the CANbus rocker switch for the SpeedSteer system is functioning and not damaged

1. 1

   Disconnect Battery

   Always disconnect the battery before servicing CANbus or steering electrical components.

2. 2

   Access Component X144

   Locate the variable steering setting potentiometer (SpeedSteer) on the steering column/dashboard assembly.

3. 3

   Test the Potentiometer

   Use a multimeter to test the resistance sweep of the X144 potentiometer. If the sweep is erratic or shows an internal open/short, the unit is defective.

4. 4

   Replace the Potentiometer

   Remove the faulty X144 potentiometer and install the replacement.

5. 5

   Reassemble and Calibrate

   Reconnect the wiring harness. Perform a calibration routine via the dealer's Electronic Diagnostic Tool (EDT) to sync the new sensor with the Autotronic 5 module.

6. 6

   Clear Codes

   Clear the D193 fault code from the instrument cluster and test the SpeedSteer function in the field (ensuring it adjusts the steering ratio correctly and shuts off above 18 km/h).