New Holland TRANS 2915 – Transmission Control Module (TRANS / TCU): 12VS1 voltage supply is low. (possible blown fuse*)

The control module is detecting a voltage drop or complete loss of 12-volt power on the specific "12VS1" power supply rail. This circuit provides power to critical transmission or implement control components. The most common cause is a blown fuse, but it can also be triggered by a short to ground in the wiring harness, a faulty power relay, or a disconnected harness.

• New Holland T7 Series (e.g., T7.175, T7.190, T7.210, T7.225)
• New Holland T8 Series (e.g., T8.275, T8.300, T8.330, T8.360, T8.390)

1. 1

   Locate the main fuse box and check if the fuse responsible for the 12VS1 circuit is blown.

2. 2

   Verify battery voltage and alternator output using a multimeter to ensure overall system voltage is acceptable.

3. 3

   If the fuse is blown, check the 12VS1 circuit wiring for a short to ground between the fuse panel and the transmission controller before replacing.

4. 4

   Test the power control relay associated with the transmission module to ensure it is closing properly and sending full voltage to the 12VS1 rail.

1. 1

   Power Down

   Turn off the tractor ignition, remove the key, and disconnect the negative battery terminal to prevent accidental shorts during repair.

2. 2

   Access the Fuse Panel

   Open the fuse panel (location varies by cab design, often on the right-hand console or behind the seat).

3. 3

   Replace the Fuse

   If the 12VS1 fuse is blown, replace it with a new blade fuse of the exact same amperage rating.

4. 4

   Trace the Short (If Applicable)

   If the new fuse blows immediately upon turning the key to the ON position, you have an active short to ground. Trace the wiring harness from the fuse block to the transmission controller (e.g., CN3 connector pins). Look for chafed wire insulation rubbing against the tractor chassis.

5. 5

   Repair Wiring

   Splice and repair any damaged wires using automotive-grade heat-shrink connectors.

6. 6

   Clear Codes

   Reconnect the battery and turn the ignition ON. Access the tractor's diagnostic menu (e.g., the H8 menu on T7/T8 models) to clear the stored EEPROM fault codes.

7. 7

   Functional Test

   Start the tractor and cycle the transmission through its gears to ensure the 12VS1 voltage remains stable and the TRANS 2915 code does not return.