Case IH 3913 – Engine Controller (EDC - Electronic Diesel Control): Active monitoring of the oxidation catalyst

The engine's control system is actively monitoring the Diesel Oxidation Catalyst (DOC) and has detected an operational anomaly. Typically, this means the DOC is failing to reach or maintain the required temperature thresholds during active regeneration, or its catalytic efficiency has degraded to the point where it cannot properly oxidize unburned hydrocarbons.

• Farmall 115U
• Magnum
• Steiger
• CR Elevation series
• CX Elevation series
• SV250
• 575N EP Backhoe

1. 1

   Check for related codes (e.g., 3914, 3915, 3916, 3917, 3918) that might prevent the DOC from heating up, as active regeneration relies on proper fuel dosing.

2. 2

   Perform a fuel system vacuum/pressure test to check for air ingress or fuel inlet restriction. Fuel pressure should be a minimum of 5 bar (72 psi) between the filter and the high-pressure pump.

3. 3

   Inspect the exhaust piping between the turbocharger and the DOC for leaks, which can cause a loss of heat.

4. 4

   Monitor the DOC inlet and outlet temperature sensors using a diagnostic tool to ensure they are reading accurately and not skewed.

1. 1

   Connect diagnostic tool

   Connect the CNH Electronic Service Tool (EST) to the machine's diagnostic port to verify code 3913 is active and review the DOC temperature logs.

2. 2

   Inspect exhaust system

   Perform a visual inspection of the exhaust system. Tighten any loose V-band clamps and replace leaking exhaust gaskets upstream of the DOC.

3. 3

   Evaluate DOC condition

   If fuel delivery and sensors are functioning normally but the DOC fails to heat up, the catalyst is likely face-plugged with soot/ash or chemically deactivated.

4. 4

   Remove temperature sensors

   Remove the exhaust temperature sensors from the DOC housing.

5. 5

   Loosen mounting hardware

   Loosen the mounting clamps and hardware securing the DOC/DPF assembly to the exhaust stream.

6. 6

   Remove DOC

   Remove the failed DOC.

7. 7

   Install new DOC

   Install the new or remanufactured DOC assembly. Always use new exhaust gaskets and locking nuts (e.g., 5/16''-18 flange nuts for heat shields) to prevent future leaks.

8. 8

   Reinstall temperature sensors

   Reinstall the temperature sensors into the new DOC housing.

9. 9

   Reset ECU timers

   Reconnect the CNH EST diagnostic tool. Clear the fault codes and reset the DOC/DPF replacement timers in the Engine ECU so the system knows a new catalyst has been installed.

10. 10

    Perform forced regeneration

    Perform a forced stationary regeneration to verify the repair. Monitor the temperatures to ensure the new DOC lights off correctly and the code does not return.