John Deere 191.17 – PTR / EPC / PTQ: Transmission Speed Sensor Speed Is Too Low During Calibration

Occurs when the engine is running and the control unit commands forward or reverse movement, but the system registers no transmission speed or a speed that is unacceptably low. This is typically caused by a faulty speed sensor, damaged wiring, or transmission solenoid valves (forward, reverse, or enable valves) being stuck closed.

• 5085E
• 5090E
• 5090EL
• 5100E
• 5045E
• 5055E
• 5065E
• 5075E
• 5065M
• 5075M
• 5085M
• 5100M
• 5100MH
• 5100ML
• 5115ML
• 5095M
• 5095MH
• 5105M
• 5015ML
• 5090M
• 5115M
• 6110R
• 6115R
• 6150M
• 6170R
• 6230
• 6330
• 6430
• 6830
• 6930
• 7210
• 7330
• 7410
• 7715
• 7720
• 7730
• 7810
• 7820
• 7830
• 7920
• 7930
• 8100
• 8200
• 8300

1. 1

   System Reset: Acknowledge the code and restart the tractor to see if communication messages correct themselves.

2. 2

   Inspect the Transmission Speed Sensor (B104) / Top Shaft Speed Sensor: Check the sensor for proper operation, ensuring it is clean, aligned correctly, and free from physical damage or debris on the tooth wheel.

3. 3

   Verify Wiring and Connections: Inspect the wiring harness and connectors related to the transmission speed sensor for signs of corrosion, chafing, or loose pins, and use a multimeter to test the sensor circuitry for short or open circuits.

4. 4

   Inspect Solenoid Valve Circuits: Verify the wiring and connections to the forward solenoid valve (Y33), reverse solenoid valve (Y36), and the proportional solenoid valve for transmission enable (Y38).

5. 5

   Test Solenoid Valve Operation: Use a diagnostic tool to test the functionality of the solenoid valves to ensure they are actuating correctly and are not stuck closed.

6. 6

   Inspect the Top Shaft: Check the top shaft and related mechanical components for obstructions or excessive wear that could cause low speed readings.

1. 1

   Repair Wiring

   If the multimeter tests reveal open or shorted circuits, repair or replace the affected sections of the wiring harness or connectors.

2. 2

   Replace the Speed Sensor

   If the wiring is intact but the transmission/top shaft speed sensor fails testing (or is physically damaged), remove the old sensor and install a new OEM replacement.

3. 3

   Replace Solenoid Valves

   If the sensor is functioning properly, replace any defective solenoid valves (Y33, Y36, or Y38) that were identified as stuck closed during diagnostic testing.

4. 4

   Mechanical Repair

   If electrical components are ruled out, the issue may be internal; install a seal kit in the transmission valve unit located on the side of the transmission, or address mechanical wear on the top shaft.

5. 5

   Reset and Calibrate

   After replacing the faulty components, clear the codes, reset the system, and test the transmission under load to ensure proper operation and that the code does not return.