Case IH 2608 (191.19) - DEC – Transmission Controller: Transmission Output Speed Sensor 1 & 2 - Abnormal Frequency Or Pulse Width Or Period on sensor 1

The signal coming from Transmission Output Speed (TOS) Sensor 1 has an 'Abnormal Frequency, Pulse Width, or Period', meaning the signal is erratic, intermittent, incorrect, or falling outside the expected operational range. This can result in harsh transmission shifting or inhibited upshifts.

• MAXXUM T4E
• Maxxum
• Puma
• Farmall
• Steiger
• Magnum

1. 1

   Check for Associated Codes: Verify if there are other active codes related to the transmission, engine speed sensors, or sensor power supply voltages.

2. 2

   Harness and Connector Inspection: Inspect the wiring harness and connectors (e.g., C100, C101, C038) associated with the transmission output speed sensor. Poor connections, dirt, or corrosion are frequent causes of this electrical fault.

3. 3

   Circuit Testing: Perform open or short-circuit tests at each harness connection between the sensor and the Transmission ECM. Check for a short to ground on each of the sensor's terminals.

4. 4

   Live Data Monitoring: Connect a diagnostic service tool to the tractor. Navigate to the monitor screen and select the transmission output speed parameter. Drive the tractor and monitor the sensor output (in RPM or MPH) to see if the signal drops out, freezes, or behaves erratically during operation.

1. 1

   Preparation

   Turn the ignition switch to the OFF position and engage the battery disconnect switch to prevent electrical shorts.

2. 2

   Locate the Sensor

   Locate Transmission Output Speed Sensor 1 on the transmission housing.

3. 3

   Disconnect Wiring

   Carefully unplug the electrical connector from the sensor.

4. 4

   Wiring Repair (If Applicable)

   If the diagnostic circuit tests revealed a wiring issue (such as a short to ground or open circuit), repair or replace the affected section of the wiring harness.

5. 5

   Sensor Removal

   If the wiring is intact and the sensor is deemed faulty, remove the retaining hardware (bolt/nut) and pull the sensor out of the transmission housing.

6. 6

   Sensor Installation

   Lubricate the O-ring on the new transmission speed sensor with clean transmission fluid. Insert the new sensor into the housing and secure it with the retaining hardware.

7. 7

   Reassembly

   Reconnect the electrical connector to the sensor, ensuring the weather seal is intact and the plug clicks into place.

8. 8

   Testing

   Turn the battery disconnect switch back on. Use the diagnostic service tool to clear the fault codes. Test drive the tractor while monitoring the live speed data to ensure the code does not return and that the transmission shifts smoothly.