John Deere SSU000517.09 – SSU: No GPS Speed Message Detected

The Steering System Control Unit (SSU) is experiencing a communication breakdown on the CAN bus and is not receiving the GPS speed data broadcast by the StarFire GPS receiver. The AutoTrac assisted steering system relies on this speed message to make accurate steering adjustments, and this missing data prevents the system from functioning properly.

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1. 1

   Restart the vehicle (turn the machine off, wait for 30 seconds, and then restart) to see if a simple power cycle clears temporary CAN bus communication glitches

2. 2

   Check for other active DTCs, particularly power supply codes like SSU 000168.03 or SSU 000168.04

3. 3

   Visually and physically inspect the StarFire receiver's 12-pin Deutsch connector for corrosion, dirt, moisture, and ensure it is securely locked

4. 4

   Inspect the wiring harness leading to the receiver for visible damage, cuts, abrasions, or pinch points

5. 5

   Verify CAN bus health on the machine's display (check for abnormally high bus utilization over 45%, and verify CAN High/Low voltages are between 1.8 and 3.3 Volts)

6. 6

   Check fuses related to the SSU and other control units (e.g., fuse F23)

1. 1

   Clean and secure connections

   If corrosion or debris is found in the StarFire connector, clean it using electrical contact cleaner. Ensure the connection is completely dry before reassembling and securely fastening.

2. 2

   Inspect wiring harness

   Thoroughly inspect the entire length of the StarFire receiver wiring harness for damage, paying close attention to areas where it may rub against the machine's frame.

3. 3

   Test harness and connector

   Disconnect the harness from the StarFire receiver and the machine. Using a multimeter, check for continuity on each wire to rule out an open circuit, and check for shorts between individual wires and to chassis ground.

4. 4

   Isolate component

   Test the system with a known-good StarFire receiver and/or wiring harness to definitively determine if the fault lies with the receiver, the wiring, or the SSU.

5. 5

   Contact technician

   If the fault persists after checking connections and harnesses, contact a certified John Deere dealer. The issue may involve a faulty SSU, a deeper CAN bus issue, or require software updates.