Case IH 2406 (519377.12) - DEC – Transmission Control Unit (TCU): Wrong Direction detected (reverse)

Control software detects the vehicle is moving in a direction opposite to the selected gear, or that the reverse drive lever position does not match the desired direction of travel.

• MAXXUM T4E
• VESTRUM CVX

1. 1

   Read out the operating data with a diagnostic tool (e.g., ZF Testman or Case IH EST) to view the freeze-frame data when the fault occurred.

2. 2

   Check the reverse drive lever (shuttle lever) position to ensure it matches the commanded direction.

3. 3

   Monitor transmission input and output speed sensors for erratic or incorrect speed readings that might trick the TCU into thinking the machine is moving backward.

4. 4

   Check transmission oil pressure and forward clutch/reverse brake commanded pressures.

1. 1

   Shift to neutral

   If the TCU detects a wrong direction, it will typically shift the transmission into neutral or a limp-home gear to protect the drivetrain. The operator must slow down the vehicle and shift the gear selector into the neutral position.

2. 2

   Verify wiring harness

   Verify the integrity of the wiring harness connecting the shuttle lever to the TCU.

3. 3

   Test and replace speed sensors

   Test and, if necessary, replace the transmission speed sensors if they are broadcasting a 'Wrong Reverse signal'.