Case IH 17662 (F-1235-11) - ECU – Engine Control Unit (ECU) / ECM: CAN Bus 2 is not functional (cannot transmit or receive messages)

The system detects that the CAN controller is defective, sending erroneous messages, or exhibiting erroneous behavior on Node 2. This is frequently caused by a 'no power' condition originating from a power or ground fault at the ATS relay, a wrong configuration of CAN timing, or a short circuit.

• VESTRUM CVX
• Austoft 9900 / 9000 Series Sugarcane Harvesters
• Farmall 115U / 120C Efficient Power Tractors

1. 1

   Check for proper power, continuity, and short circuit conditions at the ATS (Aftertreatment System) relay and its associated wiring (most common cause of CAN Bus 2 failure).

2. 2

   Inspect the CAN Bus 2 wiring harness for short circuits to an external power source, short to ground, or a short between CAN High and CAN Low.

3. 3

   Check the CAN network connections, pin contacts for corrosion, and verify the termination resistors (typically measuring ~60 ohms across CAN High and CAN Low with the battery disconnected).

4. 4

   Verify the CAN timing configuration and hardware compatibility if any modules were recently replaced or flashed.

1. 1

   Disconnect power

   Turn off the machine and disconnect the battery to ensure safety while testing the electrical network.

2. 2

   Test or replace ATS relay

   Locate the Aftertreatment System (ATS) relay in the power distribution panel. Test the relay for internal shorts or failure to close. If defective, replace the ATS relay.

3. 3

   Repair wiring harness

   If the relay is functional, trace the wiring harness from the ATS relay to the Engine ECU. Repair any broken wires, chafed insulation causing a short to ground, or corroded connector pins.

4. 4

   Verify termination resistors

   Locate the CAN bus termination resistors on the network and test them with a multimeter. Replace any burnt or out-of-spec resistors.

5. 5

   Replace Engine ECU

   If the wiring, relay, and resistors are all in good working order and the power supply to the ECU is verified, the internal CAN controller within the Engine ECU is likely defective. The ECU will need to be replaced and programmed by a dealer.

6. 6

   Clear codes

   Reconnect the battery, power on the machine, and use a diagnostic tool to clear the fault codes and verify that CAN Bus 2 communication is restored.