John Deere 177.31 – RPT: Transmission Oil Temperature Sensor, Malfunction

An open circuit is detected in the transmission oil temperature sensor circuit, causing a transmitted replacement value to be generated and potentially limiting control software functionality.

• 6110M
• 6120M
• 6130M
• 6145M
• 6155M
• 6175M
• 6195M
• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6090MC
• 6090RC
• 6100MC
• 6100RC
• 6110MC
• 6110RC

1. 1

   Inspect the wiring harness leading to the transmission oil temperature sensor for any visible signs of an open circuit, chafing, or broken wires

2. 2

   Ensure all connections to the transmission oil temperature sensor are secure

3. 3

   Disconnect the sensor and inspect the pins/terminals for corrosion, moisture, or damage. Clean any corroded connectors

4. 4

   Check the CCU or PTA modules for higher-priority codes that may be causing the RPT module to log the 177.31 fault

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to ensure safety while working on the electrical system.

2. 2

   Repair Wiring/Connectors

   If the diagnostic checks revealed broken wires or damaged connectors, repair or replace the affected sections of the wiring harness.

3. 3

   Replace the Sensor

   If the wiring and connectors are in good condition but the open circuit persists (indicating an internal open circuit within the sensor itself), remove the faulty transmission oil temperature sensor and install a new one.

4. 4

   Clear Codes and Test

   Reconnect the battery, clear the diagnostic trouble codes, and operate the tractor.

5. 5

   Monitor System Performance

   Monitor the system to ensure the fault does not recur and that the transmission temperature reads accurately on the dash/monitor.