Case IH 19387 – Engine Control Module (ECM): Timeout of CAN-Receive-Frame Torque / Speed control from ACC to ECM through TSC1_ACCE message active

A Controller Area Network (CAN) bus communication error where the Engine Control Module (ECM) does not receive the TSC1_ACCE message from the Armrest Control Computer (ACC) within the expected timeframe. This typically results in the tractor defaulting to a limp-home mode, disabling PTO functions, or limiting engine torque.

• Tier 4b
• Magnum
• Puma
• Maxxum
• Optum
• Steiger
• STM N Series

1. 1

   Perform a CAN bus resistance check with the battery disconnected by measuring resistance between CAN-High and CAN-Low at the diagnostic port (should read approximately 60 ohms)

2. 2

   Perform a CAN bus voltage check with the key ON by measuring voltage of CAN-High and CAN-Low to ground (both should rest at approximately 2.5V)

3. 3

   Verify power and ground by checking the fuses and relays powering the ACC module

4. 4

   Perform a network scan using a diagnostic tool to check for other active CAN timeout codes to determine if the entire CAN backbone is compromised

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery cable to prevent electrical spikes.

2. 2

   Inspect the Harness

   Trace the CAN bus wiring harness from the Armrest Control Computer (ACC) to the Engine ECM. Look closely for pinch points, chafing against the chassis, or rodent damage, which are the most common causes of CAN timeouts.

3. 3

   Check Connectors

   Disconnect the harness at both the ACC and the ECM. Inspect the pins for corrosion, moisture ingress, or pins that have pushed back into the connector housing.

4. 4

   Clean and Secure

   Clean any suspect pins with electronic contact cleaner, apply dielectric grease, and firmly seat the connectors.

5. 5

   Test Terminating Resistors

   If the CAN resistance check (from the diagnostic steps) failed, locate and test the CAN terminating resistors. Replace any resistor that does not measure exactly 120 ohms.

6. 6

   Restore Power and Clear Codes

   Reconnect the battery. Use the AFS Pro display (Diagnostics > Tractor > Diagnostic Trouble Codes) or a dedicated service tool to clear the inactive codes.

7. 7

   Test Operation

   Start the tractor and operate the throttle/speed controls. If the code returns immediately, and the wiring has been verified as 100% intact, the ACC module is likely failing to broadcast and will require replacement or a software re-flash by a dealer.