Case IH 2805 – TRANS (Transmission Controller): System pressure valve solenoid circuit is open circuit or shorted to ground

Triggered when the system pressure valve solenoid coil is commanded ON, but the voltage on the low side of the coil is higher or lower than expected. This indicates a break in the circuit (open), a short to ground, or a short to power in the solenoid coil or its wiring harness.

• Magnum
• Case IH Magnum 235 - 340 (Series 4)
• Case IH Steiger series
• Case IH Puma series
• Case IH MX / TG series

1. 1

   Test the system pressure valve solenoid coil with a multimeter to see if it is internally shorted or open

2. 2

   Inspect the specific wire running between the system pressure valve solenoid and the transmission controller for continuity, short to power, or short to ground

3. 3

   Check the transmission controller itself if the solenoid and the wiring harness both test perfectly

1. 1

   Prep the Machine

   Park the tractor on a level surface, engage the parking brake, relieve hydraulic system pressure, and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Solenoid

   Locate the transmission powershift valve body and identify the system pressure valve solenoid.

3. 3

   Inspect the Connector

   Disconnect the electrical harness from the solenoid. Check the connector for dirt, moisture, corrosion, or pushed-back pins. Clean with contact cleaner if necessary.

4. 4

   Test the Solenoid

   Using a digital multimeter, measure the resistance across the solenoid coil pins. If the coil reads as an open circuit (infinite resistance) or a dead short, the solenoid valve must be replaced.

5. 5

   Test the Harness

   If the solenoid is good, trace the wiring harness back to the Transmission Controller (TRANS). Check for chafed wire insulation rubbing against the tractor chassis (causing a short to ground) or broken wires (causing an open circuit). Repair any damaged sections of the harness.

6. 6

   Reassemble and Test

   Reconnect the solenoid and battery. Start the tractor and operate the transmission to see if the code clears. If the code persists and all wiring/solenoids are confirmed good, the transmission controller will need to be replaced and reprogrammed by a dealer.