Case IH 12546 – Braking System (XCM) or Cab Control Module (CCM): Pedal latch switch short to Vcc

This fault indicates that the electrical signal from the brake pedal latch switch is shorted to battery voltage (Vcc/Vbat). The brake pedal latch switch is responsible for detecting whether the left and right brake pedals are locked together (for road travel) or unlatched (for independent braking during field work).

• MAXXUM T4E
• VESTRUM CVX
• Maxxum
• Puma
• Farmall
• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070

1. 1

   Use On-Board Voltmeter Diagnostics (H9 Menu, R1 module, Channel 3) to verify the switch's live reading (should read 81 when unlatched, 30 when latched)

2. 2

   Inspect the wiring harness and connector C423 at the Brake Pedal Latch Switch (S33) for rubbed, pinched, or bare wires that could introduce a short to a 12V power source

3. 3

   Disconnect the switch and test the harness side with a multimeter; if 12V is present on the signal wire when disconnected, the harness is shorted

4. 4

   If the harness voltage is correct, test the switch itself for an internal short

1. 1

   Turn off the tractor and disconnect the battery

   This prevents electrical spikes during the repair.

2. 2

   Locate the S33 Brake Pedal Latch Switch

   Find the switch near the base of the brake pedal assembly.

3. 3

   Disconnect the C423 wiring harness connector

   Unplug the connector from the switch.

4. 4

   Repair the shorted wire

   If the diagnostic checks revealed a harness issue, trace the wiring back through electrical schematic frame 16 (A.30.A) and repair the shorted wire.

5. 5

   Remove the faulty switch

   If the switch is internally shorted, unbolt and remove the faulty switch.

6. 6

   Install the new brake pedal latch switch

   Mount the new switch and reconnect the C423 connector.

7. 7

   Reconnect the battery

   Reconnect the battery and turn the key to the ON position.

8. 8

   Verify switch states

   Use the H9 diagnostic menu (Channel 3) to verify the module now correctly reads the latched (30) and unlatched (81) states.

9. 9

   Clear the fault codes

   Clear the fault codes from the CCM/XCM.