Case IH 19844 – Engine Control Module (ECM): CAN timeout error for TSC1 Body computer/Vehicle management (Torque request to Retarder - ECM makes retarder function)

The Engine Control Module (ECM) has stopped receiving the expected TSC1 (Torque/Speed Control 1) messages from the Body Computer or Vehicle Control Module (VCM) regarding the torque request for the driveline retarder.

• Tier 4b
• Case N-Series Loader Backhoes (Tier 4 Final)
• Case IH T7 Series (Tier 4B)
• Case IH Magnum series tractors
• Case IH Steiger series tractors

1. 1

   Check for related CAN timeout codes (such as 19841, 19842, 19843, 19845, or 19846) which indicate a broader CAN bus failure rather than a single module issue.

2. 2

   With the battery disconnected, measure the resistance across the CAN High and CAN Low pins (a healthy CAN bus should read approximately 60 ohms).

3. 3

   Analyze resistance readings: 120 ohms indicates a missing/failed terminating resistor or damaged wiring; infinite resistance (open) indicates a broken wire or disconnected connector.

4. 4

   Verify that the Body Computer/VCM has proper battery voltage and clean ground connections, as a module losing power will stop transmitting CAN messages.

1. 1

   Disconnect battery

   Disconnect the machine's battery power to prevent electrical shorts during testing.

2. 2

   Locate harness

   Locate the CAN bus wiring harness connecting the Body Computer/VCM to the ECM.

3. 3

   Inspect connectors

   Inspect the wiring harness connectors at both modules. Look for pushed-out pins, corrosion, moisture, or damaged wires.

4. 4

   Trace CAN lines

   If the CAN bus resistance test (performed in the diagnostic steps) yielded 120 ohms or an open circuit, trace the CAN lines to locate the physical break or locate the missing/damaged 120-ohm terminating resistor. (Note: The ECM typically has an internal terminating resistor, while the other is located on the harness or inside another module).

5. 5

   Repair or replace harness/resistor

   Repair any chafed or broken wires in the CAN harness, or replace the harness/terminating resistor as necessary.

6. 6

   Reconnect modules

   Reconnect all modules and restore battery power.

7. 7

   Clear codes and verify

   Connect the Electronic Service Tool (EST) to clear the inactive fault codes and verify that the TSC1 CAN communication has been restored.

8. 8

   Replace or re-flash VCM

   If the wiring and resistors are perfectly intact and the code remains active, the Body Computer/VCM may have failed internally and will require replacement or a software re-flash.