Case IH 3599 – Engine Control Unit (ECU): Error path of oxidation catalyst not present - Warm Up Catalyst Efficiency Below Threshold

The engine control system has detected that the Diesel Oxidation Catalyst (DOC) is not warming up as expected, or the temperature ratio between the upstream and downstream exhaust temperature sensors has fallen below the acceptable threshold during the warm-up phase.

• Steiger (350, 400, 450, 500, 550, 600)
• Quadtrac
• Rowtrac
• Magnum
• Puma
• Maxxum
• Optum
• Farmall (105A, 110C, 115U)
• Axial-Flow Combines (7240, 8240, 9240)

1. 1

   Visual Inspection: Check the muffler and catalyst assembly for physical damage.

2. 2

   Exhaust Leaks: Check that the exhaust gas piping is mounted correctly and verify there are no exhaust leaks prior to or across the catalyst.

3. 3

   Sensor Installation: Ensure that the upstream and downstream exhaust temperature sensors are installed correctly and securely.

4. 4

   Sensor Accuracy: Use the CNH Electronic Service Tool (EST) to monitor and check the exhaust temperature sensors for accuracy.

1. 1

   Inspect and Verify

   Perform the visual and EST diagnostic checks listed above to rule out exhaust leaks or wiring issues.

2. 2

   Replace Sensors

   If the EST shows that the upstream or downstream exhaust temperature sensors are reading inaccurately or failing to register heat changes, replace the faulty sensor(s).

3. 3

   Replace Catalyst

   If the sensors are accurate and there are no exhaust leaks, the Diesel Oxidation Catalyst (DOC) itself has likely degraded and can no longer reach the required efficiency threshold. The DOC/muffler assembly must be replaced.

4. 4

   System Reset and Validation

   Clear the codes using the EST, bring the engine up to operating temperature, and run the machine under load to validate the repair.