Case IH 19470 – Engine Control Module (ECM): SCB at the High side and SCG at the Low side of Exhaust flap powerstage

The exhaust flap (exhaust brake valve) restricts exhaust flow to load the engine and heat the DOC and SCR catalyst. This fault code indicates a critical electrical failure: a short circuit to battery on the high side and a short circuit to ground on the low side of the actuator's internal power stage or its immediate wiring.

• Tier 4b
• Vestrum 100
• Vestrum 110
• Vestrum 120
• Vestrum 130
• Maxxum 115
• Maxxum 125
• Maxxum 135
• Maxxum 145
• Farmall 110A
• Farmall 120A
• Farmall 130A
• Farmall 140A
• Magnum
• Steiger
• Quadtrac

1. 1

   With the key OFF, manually move the exhaust flap actuator to check for mechanical binding; it should move through its full stroke with little resistance.

2. 2

   Inspect the wiring harness and connector going to the exhaust flap actuator for chafed wires causing a short circuit to an external power source (SCB) or to the chassis ground (SCG).

3. 3

   Verify the power supply and CAN lines at the actuator connector (Pin 1: +30 Power Supply, Pin 2: Ground, Pin 3: CAN-L, Pin 4: CAN-H).

1. 1

   Clear Carbon Build-up

   If the manual check revealed a stuck flap, remove the actuator linkage and clean any carbon build-up from the exhaust flap valve inside the exhaust pipe to free the mechanism.

2. 2

   Repair Wiring

   If the wiring harness is damaged, repair the shorted wires on the high side (power) or low side (ground) circuits leading to the ECM.

3. 3

   Replace the Actuator

   If the flap moves freely and the external wiring is intact, the internal power stage of the electromechanical actuator has failed. Drain the engine coolant, disconnect the electrical connector, unbolt the actuator from the exhaust manifold, and install the replacement unit.

4. 4

   Validate Repair

   After replacing the actuator or cleaning the flap, run the engine under full load for 1 hour to ensure the exhaust system reaches operating temperature and to verify the symptom does not reoccur.