Case IH 19198 – Engine Control Module (ECM) or Vehicle Control Module (VCM): Plausibility check error of the intake manifold air temperature sensor at cold start only

The temperature reading being sent from the intake manifold air temperature sensor to the computer during a cold start is outside of the expected or logical operating range (implausible). This can be caused by a failed sensor, a wiring issue (open or short circuit), or operating the machine in extreme cold weather that falls below the sensor's minimum temperature threshold.

• Tier 4b
• Farmall series (40, 45, 50, 115U)
• Magnum series (215, 225, 245, 250, 275, 280, 305, 310, 335)
• Steiger / STX series (280, 330, 335)
• Axial-Flow series (2366, 2377, 2388, 2577, 2588, 5088, 6088, 7088)
• N-Series TLBs (Tier 4 Final)
• Cotton Express and Module Express Pickers (420, 620, 625)

1. 1

   Verify environmental conditions: If starting in temperatures below 20–25°F, the sensor may throw a false plausibility error. Let the machine warm up to see if the code clears.

2. 2

   Locate the intake manifold air temperature sensor on the left side of the engine cylinder head or directly on the intake pipe.

3. 3

   Inspect the sensor wiring harness (often Pin 38 on Cummins/CNH applications) for low voltage, open circuits, or shorts to ground.

4. 4

   Inspect the sensor tip for heavy soot buildup or physical damage that could skew temperature readings.

1. 1

   Turn off the machine, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Locate the intake manifold air temperature sensor on the left side of the engine cylinder head/intake manifold.

3. 3

   Depress the locking tab and disconnect the electrical harness from the sensor.

4. 4

   Using the appropriate wrench, carefully unscrew the faulty temperature sensor from the intake manifold.

5. 5

   Clean the mating threads on the manifold to ensure a good seal.

6. 6

   Thread the new OEM sensor into the manifold and tighten it to the manufacturer's specified torque.

7. 7

   Reconnect the electrical harness connector, ensuring it clicks securely into place.

8. 8

   Reconnect the battery and start the engine. Allow the engine to reach normal operating temperature to verify that the cold start plausibility code (19198) has cleared.