John Deere 000191.17 – Transmission Control Unit: Transmission Speed Sensor Speed Too Low During Calibration or Operation

The transmission control module has detected that the transmission's output shaft speed is too low or non-existent when it is expected to be turning. This can occur during a calibration procedure or during normal operation when the tractor is commanded to move. The code signifies that the data from the transmission speed sensor is valid but below the normal operating range, indicating a discrepancy between the commanded state and the actual transmission output. This typically results in the tractor failing to move or stopping shortly after starting.

• 5075E
• 6105E
• 6140R
• 6430 Premium
• 6230
• 5075M

1. 1

   Check for other active or stored fault codes, as 000191.17 can sometimes be a symptom of a broader electrical or communication issue

2. 2

   Inspect the wiring harness and connectors associated with the transmission speed sensor for any signs of damage, corrosion, or loose connections. The sensor is often located on the transmission or final drive housing

3. 3

   Verify the transmission hydraulic oil level is correct and inspect the fluid for contamination or signs of internal wear (e.g., metal shavings). A clogged hydraulic filter can also cause issues

4. 4

   Test the transmission speed sensor's resistance with a multimeter. For example, on a 6140R, the resistance across specific pins should be approximately 3300 ohms

5. 5

   Verify for a 12V supply and good continuity to ground at the sensor's harness connector

6. 6

   Inspect the neutral safety switch and its wiring for proper operation, as a faulty switch can trigger this code on some models

7. 7

   Measure the transmission's hydraulic pressures and compare them to factory specifications to help identify internal mechanical problems like a slipping clutch

1. 1

   Address electrical faults

   If diagnostic checks reveal damaged wiring, corroded connectors, or a faulty sensor, replace the affected components.

2. 2

   Replace transmission speed sensor

   If the sensor is determined to be faulty, it will need to be replaced. On some models, like the 6430, this may require tilting the cab for access.

3. 3

   Replace neutral safety switch

   If the neutral safety switch is identified as the cause, replace it. This is often located near the gear shift linkage.

4. 4

   Perform transmission calibration

   After replacing electrical components or if no physical faults are found, a transmission calibration using dealer-level diagnostic software (Service Advisor) may be necessary. This can resolve issues related to clutch fill times and pressures.

5. 5

   Address internal mechanical failures

   If diagnostics point to internal transmission problems, such as a slipping clutch, the transmission will likely require disassembly for further inspection and repair by a qualified technician.