John Deere 177.01 – SCC, SCO, SIC, TCU, PTP: Hydraulic Oil Temperature Too Low / Transmission Oil Temperature Too Low

The Transmission Control Unit (TCU) has detected that the transmission oil temperature is below the normal operating range (SPN 177, FMI 01). This indicates the sensor reading is colder than the minimum threshold, which may affect proper transmission operation. While this can be caused by a genuine low temperature condition, it is most commonly due to a faulty transmission oil temperature sensor or damaged wiring.

• 6110R
• 6120R
• 6130R
• 6145R
• 6155R
• 6175R
• 6195R
• 6215R
• 6230
• 6330
• 6430
• 7430
• 7530
• 8245R through 8400R
• 9470RT
• 9520RT
• 9570RT
• 5075GV
• 5090GV
• 5105GN
• 7180
• 7280
• 7380
• 7480
• 7580
• 7780
• 7980

1. 1

   Verify the current hydraulic/transmission oil temperature via the cab's CommandCenter display

2. 2

   Determine if the machine has been sitting in cold weather and simply needs time to warm up

3. 3

   Check for accompanying electrical fault codes (e.g., 177.03, 177.04, 177.05, 177.06) that indicate a hard electrical failure in the sensor wiring rather than cold oil

1. 1

   Warm Up the System

   Start the engine and allow the tractor to idle. Operate the equipment's hydraulic functions (such as deadheading an SCV or cycling the steering) to safely build heat in the hydraulic system.

2. 2

   Reach Target Temperature

   Continue warming the system or use external block/fluid heaters until the hydraulic oil temperature exceeds 40°C (104°F).

3. 3

   Clear and Calibrate

   Once the oil is sufficiently warmed, cycle the key switch to clear the code. If you were attempting a front hitch calibration, restart the calibration procedure.

4. 4

   Inspect the Sensor Circuit

   If the code persists even when the oil is physically hot to the touch, inspect the wiring harness leading to the Transmission/Hydraulic Oil Temperature Sensor. Look for chafed wires, corroded connector pins, or a disconnected plug.

5. 5

   Test/Replace the Sensor

   Use a multimeter to test the resistance of the temperature sensor. If the sensor reads an open circuit or is reporting a falsely cold temperature out of specification, drain the fluid below the sensor port level and replace the sensor.