Case IH 3202 – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): Cylinder5 Warning - Fast Decay Error

This code indicates an electrical fault in the fuel injector circuit for Cylinder No. 5. The Engine Control Unit monitors the 'fast decay' impulse—the rapid discharge of electrical energy (current) when the injector solenoid is de-energized. If the recovered switch-off energy is insufficient or the current drops too quickly/slowly, the ECU logs a fast decay error. This typically points to a failed injector solenoid, a short circuit, or a damaged electrical harness in the No. 5 cylinder circuit. As a fail-safe, the ECU may stop operating the No. 5 cylinder injector.

• Case IH Magnum Series: 180, 200, 215, 220, 235, 240, 245, 250, 280, 305, 310, 335, 340 (Series 4)
• Case IH Steiger 4WD Tractors: 370, 420, 470, 500
• Case IH Puma Series
• Case IH Maxxum Series

1. 1

   Inspect the electrical harness and connectors leading to the No. 5 cylinder injector for chafed wires, open loads, or short circuits to ground or battery.

2. 2

   Disconnect the No. 5 injector and the Engine ECU connectors. Check for corrosion, bent pins, or moisture intrusion.

3. 3

   Measure the resistance of the No. 5 fuel injector solenoid with a multimeter. Compare the reading to OEM specifications to determine if the internal solenoid has failed.

4. 4

   Swap the No. 5 injector electrical connector with an adjacent cylinder (if harness length permits) to see if the fault code moves to the new cylinder (e.g., Code 3206 for Cylinder 6). If the code moves, the injector is faulty; if it stays as 3202, the harness or ECU is faulty.

1. 1

   Preparation

   Turn off the engine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Access

   Remove the engine valve cover or acoustic panels as necessary to access the fuel rail and injectors.

3. 3

   Disconnect Electricals

   Carefully unplug the electrical connector from the No. 5 fuel injector. If the harness was diagnosed as faulty in the previous steps, repair or replace the injector wiring harness section.

4. 4

   Remove Fuel Line

   Loosen and remove the high-pressure fuel injection line/tube connected to Cylinder 5. (Note: High-pressure fuel lines are often single-use and should be replaced to prevent leaks).

5. 5

   Remove Injector

   Unbolt the injector hold-down clamp and carefully extract the No. 5 fuel injector from the cylinder head.

6. 6

   Install New Injector

   Clean the injector bore. Install the new or remanufactured fuel injector with a new sealing washer/O-ring. Torque the hold-down clamp to OEM specifications.

7. 7

   Reassemble

   Install the new high-pressure fuel line for Cylinder 5 and torque the fittings. Reconnect the electrical connector.

8. 8

   Finalize

   Reconnect the battery. Bleed the fuel system if required by the specific engine manual.

9. 9

   Clear Codes

   Use a diagnostic scan tool to clear the 3202 fault code. Start the engine and verify that the code does not return and the engine runs smoothly.