New Holland ENG 3238 – Engine Control Module (ECM) / Electronic Diesel Control (EDC): EDC SPI: ECM Internal SPI Communication Error - CJ940

This fault code indicates a critical internal hardware or software failure within the engine's computer. It flags a communication breakdown involving the internal chip designated as CJ940, meaning the engine controller is failing to process its own internal logic correctly.

• T6
• T7
• T8.xxx Series
• T6000 Series
• CX Series (CX7080, CX8090, etc.)
• CR Series
• B110B Backhoe Loaders
• W-Series Wheel Loaders
• Magnum Series (235-340)
• Puma Series
• Steiger
• F-Series Wheel Loaders (721F, 821F, 921F)

1. 1

   Connect the CNH Electronic Service Tool (EST) to determine if the code is active or stored. Clear the DTCs; if the code does not return, it may have been a temporary software glitch.

2. 2

   Load-test the batteries and inspect the main power and ground cables feeding the ECM to rule out voltage spikes, severe voltage drops, or poor grounding.

3. 3

   Disconnect the ECM harnesses and check for water ingress, corrosion, or bent pins, which can short internal circuits.

4. 4

   Check if there is a software update/reflash available for the ECM that addresses internal watchdog or SPI communication bugs.

1. 1

   Disconnect battery

   Disconnect the machine's battery (negative terminal first) to prevent electrical arcing.

2. 2

   Locate ECM

   Locate the Engine Control Module (typically mounted on the side of the engine block, utilizing vibration isolators).

3. 3

   Unplug ECM

   Carefully release the locking levers on the ECM wiring harness connectors and unplug them.

4. 4

   Remove ECM

   Remove the mounting bolts and remove the faulty ECM.

5. 5

   Install new ECM

   Install the new ECM and torque the mounting bolts to OEM spec. Do not over-tighten, as this can damage the vibration isolators.

6. 6

   Reconnect harnesses

   Reconnect the wiring harnesses, ensuring the locking levers click fully into place.

7. 7

   Reconnect battery

   Reconnect the battery.

8. 8

   Program ECM

   Connect the CNH EST diagnostic tool. The blank replacement ECM must be flashed/programmed with the correct software payload (dataset) specific to the machine's PIN/Serial Number.

9. 9

   Perform calibrations

   Perform any required engine calibrations (e.g., injector coding) and clear all historical fault codes.