New Holland ENG 3537 – Engine ECU (Engine Control Module): CAN Message timeout DM1DCU (from DCU) - CAN timeout

The Engine Control Unit (ECU) has stopped receiving the expected Diagnostic Message 1 (DM1) from the Dosing Control Unit (DCU) within the allotted time limit.

• T7 Series (T7.220, T7.235, T7.250, T7.260, T7.270)
• T8 Series
• T9 Series
• CX Series (CX8080, CX8090)
• CR Series (CR9090)
• New Holland / FPT Engines

1. 1

   Check for multiple CAN bus fault codes, which indicates a global CAN bus failure rather than an isolated DCU issue

2. 2

   Verify DCU power and ground by checking the fuses and relays supplying the DCU

3. 3

   Perform a CAN bus resistance test with the battery disconnected across the CAN HI (yellow) and CAN LO (green) wires (should read 60 ohms)

4. 4

   Visually inspect the wiring harness between the Engine ECU and the DCU for chafing, corrosion, or backed-out pins in the connectors

1. 1

   Verify the Fault

   Turn the key ON and verify if ENG 3537 is currently active.

2. 2

   Isolate the Wiring

   If the CAN resistance test fails, trace the CAN HI and CAN LO wires between the ECU and DCU. Repair any broken wires or replace damaged connector pins.

3. 3

   Check Terminating Resistors

   If the resistance is 120 ohms, locate and test the CAN terminating resistors. Replace the failed resistor if it does not measure 120 ohms independently.

4. 4

   Replace the DCU

   If the wiring harness is intact, terminating resistance is exactly 60 ohms, and the DCU is receiving proper power and ground, the DCU itself has suffered an internal failure and must be replaced.

5. 5

   Program the New DCU

   A replacement DCU is not plug-and-play. It requires software installation and programming using the OEM diagnostic tool (EST). Note: CNH requires troubleshooting to be completed before issuing programming passwords.

6. 6

   Clear and Retest

   Clear the fault codes from the Engine ECU and cycle the key to ensure the code does not return.