Case IH 3374 – Engine Controller (Engine ECU / ECM): Injector Codes Not Valid In Controller Memory. Write Correct Injector Codes With Service Tool

This fault indicates that the Engine Control Unit (ECU) has detected missing, corrupt, or invalid fuel injector calibration codes (Injection Quantity Adjustment or IQA codes) in its EEPROM memory.

• Farmall
• skid steer
• Machines equipped with FPT F5C engines
• Case IH Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• Case IH Magnum 235 - 340 (Series 4)

1. 1

   Check service history to determine if the Engine ECU was recently replaced, updated, or reprogrammed.

2. 2

   Check if any fuel injectors were recently replaced without programming the new injector codes into the ECU.

3. 3

   Visually inspect the fuel injectors and write down the alphanumeric calibration code printed on each, noting the corresponding cylinder.

1. 1

   Connect Diagnostic Tool

   Connect the Case IH Electronic Service Tool (EST) laptop to the machine's diagnostic port.

2. 2

   Read Injector Codes

   Physically verify the IQA/calibration codes printed on the installed fuel injectors.

3. 3

   Access Engine Controller

   Open the engine controller module in the service tool software and navigate to the injector programming or calibration menu.

4. 4

   Write Codes

   Manually enter the correct alphanumeric injector codes into the ECU memory for each corresponding cylinder.

5. 5

   Save and Reset

   Save the configuration to the ECU's EEPROM. Turn the machine's key switch to the OFF position and wait for the ECU to fully power down and save the parameters.

6. 6

   Verify Repair

   Turn the key back on, reconnect the service tool, and clear the fault codes. Start the engine and verify that fault code 3374 does not return. Note: If the ECU refuses to accept the codes or the code immediately returns after a key cycle, the Engine ECU's internal EEPROM may be physically damaged, requiring ECU replacement.