Case IH 19039 (F-5318-02) - ECU – Engine ECU / Aftertreatment Control Module: Exhaust gas temperature sensors signal drift at cold start only

The Engine Control Unit is comparing the reading from the upstream oxidation catalyst (DOC) temperature sensor during a cold start against a calculated expected temperature (often based on ambient and coolant temperatures), and the sensor's signal is drifting outside the acceptable range.

• VESTRUM CVX
• Farmall 40
• Farmall 45
• Farmall 50
• 240 Series Axial-Flow Combines
• Maxxum
• Puma
• Magnum
• Farmall 100C-120U

1. 1

   Connect a diagnostic tool before starting the engine for the day and compare the upstream oxidation catalyst temperature sensor reading to the ambient air temperature and engine coolant temperature. A significant variance indicates sensor drift.

2. 2

   Check for accompanying codes that might indicate a broader circuit issue, such as 19040, 19041 (Upstream SCR temperature sensor comparison failure), or 19066 (Upstream oxidation catalyst temperature sensor voltage is higher than expected).

3. 3

   Inspect the sensor's 2-pin Bosch plug and the wiring harness leading to the ECU for chafing, corrosion, or loose connections.

1. 1

   Locate the upstream oxidation catalyst (DOC) temperature sensor on the exhaust aftertreatment assembly.

   It is often routed near the turbo elbow bracket.

2. 2

   Disconnect the electrical connection.

   Standard 2-pin Bosch plug.

3. 3

   Remove any retaining clips or clamps securing the exhaust gas temperature sensor wiring to the turbo elbow bracket or heat shields.

   e.g., clamp part #362667R1.

4. 4

   Using a wrench, carefully unthread the temperature sensor from the exhaust pipe.

   The sensor utilizes an M14x1.5 thread connection.

5. 5

   Apply a small amount of anti-seize to the threads of the new sensor (if not pre-applied) and thread it into the exhaust housing.

   Tighten to OEM specifications.

6. 6

   Route the new sensor's cable along the factory path, securing it with the retaining clips to prevent melting against the exhaust.

   Cable length is typically around 21.65 inches.

7. 7

   Reconnect the 2-pin Bosch plug to the engine harness.

8. 8

   Clear the fault codes using a diagnostic tool and perform a cold start to verify the signal drift is resolved and the code does not return.