Case IH 399 – Engine Control Module (ECM): Rear Timing current is too high

The Engine Control Module (ECM) has detected a high current or a grounded circuit at the rear timing actuator (Timing Actuator #2). When this occurs, the engine timing actuator is not responding correctly to ECM commands, which can cause the cylinders in the rear bank to not receive proper fuel timing, leading to a loss of performance or the engine running on only the front cylinders.

• MX Magnum
• STX Steiger
• Magnum
• Steiger

1. 1

   Inspect the wiring harness between the ECM and the rear timing actuator for any signs of chafing, bare wires, or a short to ground.

2. 2

   Disconnect the rear timing actuator and measure the resistance across the pins on the actuator coil. A healthy actuator typically reads between 1.0 and 1.5 ohms. If out of range, the actuator has failed internally.

3. 3

   Check the ECM connector pins (often pins 55 and 56 for the rear timing actuator) for corrosion, moisture, or pushed-back pins.

1. 1

   Preparation

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

2. 2

   Locate the Actuator

   Locate the fuel delivery housing / Integrated Fuel System Module (IFSM) on the engine. Identify the rear timing actuator (usually grouped with the front timing, front fueling, and rear fueling actuators).

3. 3

   Removal

   Disconnect the electrical connector from the rear timing actuator. Remove the mounting screws holding the actuator in place and pull the actuator out.

4. 4

   Cleaning

   Carefully clean the mounting surface on the fuel housing, ensuring no debris falls into the fuel system.

5. 5

   Installation

   Install the new rear timing actuator along with its new gasket/O-rings.

6. 6

   Torque

   Tighten the mounting screws to the manufacturer's specification (commonly 135 in/lbs for these Cummins/Case IH actuators).

7. 7

   Reassembly

   Reconnect the electrical harness to the actuator and reconnect the battery.

8. 8

   Purge Air and Test

   Start the engine and let it run outside to purge all air out of the fuel system. Inspect the actuator area closely for any fuel leaks.

9. 9

   Clear Codes

   Use a diagnostic tool or CAN-bus eraser to clear the inactive fault codes from the ECM.