Case IH F-629-14 - ECU – Engine Control Unit (ECU): ECU internal failure - ECU shutdown test failure

This code indicates an internal hardware or logic failure within the engine's computer during its self-check routines. The ECU attempts to verify that it can successfully deactivate all power stages relevant to fuel injection in the event of a critical error. If the ECU detects an incorrect response to the power stage supply during this internal test, it logs this fault code.

• MAGNUM AFS Connect
• 240 Series Axial-Flow Combines
• N-Series Loader Backhoes
• TC-series hydrostatic machines

1. 1

   Clear the fault code using a diagnostic tool and cycle the machine to see if the system operates normally and if the code returns, ruling out a transient software glitch.

2. 2

   Disconnect the ECU harnesses and inspect the pins for corrosion, moisture, or pushed-out pins.

3. 3

   Check the engine wiring harness for chafing, shorts to ground, or shorts to power, particularly on the power supply lines to the ECU.

1. 1

   Power down the machine and engage the parking brake.

2. 2

   Locate the Engine Control Unit (ECU) on the engine block or firewall.

3. 3

   Carefully disconnect the main wiring harness connectors from the ECU.

4. 4

   Perform a visual and multimeter continuity check on the harness to ensure the ECU is receiving proper voltage and ground.

5. 5

   Clean the connectors with electrical contact cleaner and apply dielectric grease. Reconnect and test the machine.

6. 6

   If the wiring is intact and the F-629-14 code immediately returns upon startup, the internal circuitry of the ECU has failed.

7. 7

   Remove the defective ECU and install a replacement unit.

8. 8

   Using the Case IH Electronic Service Tool (EST), flash/program the new ECU with the correct software payload for the specific machine's PIN/Serial Number.