Massey Ferguson T253 – Transmission Control Module (TRANS / TRANS2) / Autotronic 5: Transmission Pressure Switch Open When Engine Is Running

The Low-pressure switch (20 bar / 290 psi) is reading an open circuit while the engine is running (often monitored at or above 500 rpm). This indicates that the transmission control system is either detecting dangerously low hydraulic pressure in the transmission circuit, or the switch/wiring itself has failed and is falsely reporting an open circuit, forcing the tractor into limp mode and illuminating the transmission oil pressure lamp.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 6480
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726

1. 1

   Check transmission hydraulic oil level and condition

2. 2

   Inspect transmission filters for severe clogs; cut open old filters to check for excessive debris or metal shavings indicating internal failure

3. 3

   Connect a mechanical hydraulic pressure gauge to the transmission test port to verify if the system is actually producing the required 20 bar (290 psi) of pressure

4. 4

   Inspect the wiring harness and connections leading to the 20 bar transmission pressure switch for disconnected plugs, broken wires, or corrosion

1. 1

   Locate the Switch

   Identify the 20 bar transmission low-pressure switch on the transmission valve block/housing.

2. 2

   Resolve Wiring Issues

   If the diagnostic checks revealed a broken wire or corroded connector, repair the harness and clear the code.

3. 3

   Replace the Switch

   If mechanical pressure is confirmed to be good (above 20 bar) but the code persists and wiring is intact, the switch has failed internally. Disconnect the electrical connector, unscrew the faulty pressure switch, install the new 20 bar pressure switch and tighten to OEM torque specifications, then reconnect the electrical harness.

4. 4

   Address Internal Pressure Loss

   If the mechanical gauge confirmed that transmission pressure is actually dropping below 20 bar, replacing the switch will not fix the issue. You must address the root cause of the pressure loss (e.g., replacing clogged filters, repairing a failing transmission hydraulic pump, or fixing internal leaks).

5. 5

   Clear Codes

   Use a diagnostic tool to clear the T253 code from the Autotronic 5 / TRANS module and test drive the tractor to ensure the transmission pressure lamp remains off.