Case IH F-5318-02 - ECU – Engine Control Unit (ECU) / Electronic Diesel Control (EDC): Exhaust Temp monitoring diagnostic fault: Exhaust gas temperature sensors signal drift at cold start

The ECU has detected that two or more temperature sensors are not plausible after a long standstill time. During a cold start, the exhaust gas temperature sensors should read roughly the same ambient temperature as the engine coolant. If one or more sensors drift outside of a 10°C tolerance compared to the coolant temperature, this fault is logged.

• MAGNUM AFS Connect
• Farmall
• Maxxum
• Puma
• Steiger
• Combine Harvesters

1. 1

   Cold Soak the Machine: Ensure the machine has been turned off and sitting for at least 10 hours to achieve a true cold start condition.

2. 2

   Compare Temperatures: Connect a diagnostic tool and read the engine coolant temperature alongside all exhaust gas temperature sensors.

3. 3

   Check Tolerances: Verify that all exhaust gas temperatures are within 10°C of the coolant temperature to identify the drifting sensor.

4. 4

   Inspect Wiring: Check the wiring harness and connectors of the suspect sensor for correct isolation, proper contact, corrosion, or short circuits to an external source.

1. 1

   Turn off the machine and allow the exhaust system to cool completely if it has been running.

2. 2

   Locate the specific exhaust gas temperature sensor that failed the 10°C tolerance check (e.g., Catalyst Inlet, DPF Inlet, or SCR Upstream/Downstream).

3. 3

   Disconnect the sensor's electrical connector and inspect the pins. If damaged, repair the harness.

4. 4

   If the wiring is intact, remove the faulty exhaust gas temperature sensor from the exhaust pipe/manifold using the appropriate wrench (often a 17mm).

5. 5

   Apply a small amount of anti-seize compound to the threads of the new sensor (if not pre-applied) and install it into the exhaust system. Torque to OEM specifications.

6. 6

   Reconnect the electrical harness.

7. 7

   Connect the diagnostic tool, clear the fault codes, and perform a key cycle to verify the repair.

   If the fault caused an SCR inducement (derate), you may need to perform an "Inducement Unlock / Counter Reset" via the diagnostic tool.