New Holland ENG 412 – ENGINE: J1708 data link cannot transmit

The controller is physically unable to send data out onto the J1708 network. This is typically caused by electrical interference, an open or shorted wire in the data link harness, a failed termination resistor, or a hardware failure within the module's communication transceiver.

• T7 Series tractors
• T7.270
• CE Off-Highway equipment
• D350 Dozers

1. 1

   Check for electrical interference on the SAE J1708 link, ensuring no aftermarket devices are corrupting the signal.

2. 2

   Use a diagnostic tool (VCADS Pro, CNH EST, or JPRO) to run a vehicle information test and verify communication with all control units.

3. 3

   Disconnect battery power and measure the resistance across the data link circuit; a reading greater than 140 ohms indicates a termination resistor or wiring issue.

4. 4

   Inspect the diagnostic port (Deutsch HD10) and Engine ECU pins for corrosion, moisture, or pushed-out pins.

1. 1

   Power Down

   Turn off the key switch and disconnect the battery to prevent electrical damage during testing.

2. 2

   Harness Inspection

   Trace the J1708 wiring harness from the Engine ECU to the diagnostic connector. Look for chafed wires, pinched harnesses, or melted insulation. Repair any damaged sections of the wire.

3. 3

   Resistor Replacement

   If the resistance test yielded >140 ohms, locate the J1708 termination resistors in the harness. Replace the faulty resistor(s) to restore the proper circuit resistance.

4. 4

   Connector Repair

   If the diagnostic connector or ECU connector is damaged, replace the faulty pins or the connector body (e.g., Deutsch HD10 connector replacement).

5. 5

   ECU Verification

   If the wiring harness, connectors, and resistors all test perfectly, the Engine ECU itself has suffered an internal hardware failure on its J1708 transceiver. The ECU will need to be replaced or sent out for repair.

6. 6

   Clear Codes

   Reconnect the battery, connect a dealer diagnostic tool, and clear the fault codes to verify the repair has eliminated the problem.