Case IH 3513 – Engine Control Unit (ECU / ENG): SCR Catalyst not present _Relation of temperature behavior between both Catalyst Temperatures not plausible

The Engine Control Unit (ECU) is reading implausible data between the pre-catalyst and post-catalyst Exhaust Gas Temperature (EGT) sensors. The ECU expects a specific thermal behavior (temperature drop and heating rate) across the Selective Catalytic Reduction (SCR) catalyst due to its physical thermal mass and the chemical reactions taking place. When the temperature relationship between the inlet and outlet sensors does not match the expected mathematical model, the ECU suspects that the SCR catalyst has been removed, hollowed out, or that the temperature sensors are malfunctioning, swapped, or reading incorrectly.

• Case IH Magnum series (235, 260, 290, 310, 340, 380)
• Case IH Steiger / Quadtrac series (370, 400, 450, 470, 500, 540, 580, 600)
• Case IH Puma series
• Case IH Maxxum series
• Case IH Patriot Sprayers
• Case IH TR340 Compact Track Loaders

1. 1

   Visual Inspection of the SCR: Physically inspect the exhaust system to ensure the SCR catalyst is actually present, intact, and has not been illegally hollowed out, bypassed, or modified.

2. 2

   Wiring and Connector Check: Inspect the wiring harnesses for both the pre-SCR and post-SCR temperature sensors. Look for chafed wires, melted insulation, or corrosion in the connectors. Ensure the connectors for the upstream and downstream sensors have not been accidentally swapped during previous maintenance.

3. 3

   Cold Engine Live Data: Connect the Electronic Service Tool (EST). With the engine completely cold (sitting overnight), check the live data for both SCR temperature sensors. Both should read identically to the ambient air temperature. If one reads significantly higher or lower, that sensor is faulty.

4. 4

   Hot Engine Live Data: Run the engine and monitor the temperature sensors. Look for a sensor that is stuck at a specific value, dropping out to default extremes, or reacting too erratically compared to the gradual heating of the exhaust.

1. 1

   Turn off the machine, remove the key, and disconnect the battery ground

   to ensure safety while working on the exhaust and electrical systems.

2. 2

   Replace the entire SCR muffler assembly

   If the physical SCR catalyst is missing or internally destroyed.

3. 3

   Locate the failed sensor

   If the diagnostics point to a faulty Exhaust Gas Temperature (EGT) sensor (either upstream or downstream of the SCR catalyst).

4. 4

   Disconnect the faulty sensor's electrical connector

   from the main engine wiring harness.

5. 5

   Apply penetrating oil to the threads of the sensor in the exhaust pipe and allow it to soak

   as exhaust sensors are highly prone to seizing.

6. 6

   Carefully unscrew the sensor using a specialized sensor socket or wrench

   to avoid stripping the threads in the exhaust housing.

7. 7

   Apply a small amount of high-temperature anti-seize compound to the threads of the new EGT sensor

   (if it does not come pre-applied from the factory). Do not get anti-seize on the sensor probe itself.

8. 8

   Thread the new sensor into the exhaust housing and tighten

   to the OEM torque specification.

9. 9

   Route the sensor wire safely away from extreme heat sources and reconnect it

   to the wiring harness.

10. 10

    Reconnect the battery, connect the EST, and clear fault code 3513.

11. 11

    Perform a forced stationary regeneration or a test drive under load

    to verify that the temperature differential across the catalyst is now reading plausibly and the code does not return.