Case IH 19197 (F-172-02) - ECU – Engine Control Unit (ECU): Plausibility check error of the first fresh air temperature sensor at cold start.

During an engine cold start, the Engine Control Unit (ECU) monitors up to five different temperature sensors to check for mutual plausibility. If the first fresh air temperature sensor (B-185) provides a reading that is significantly out of range compared to the other sensors, the ECU flags this plausibility error.

• VESTRUM CVX
• Austoft 9000
• Austoft 9900
• N-Series TLBs

1. 1

   Connect a diagnostic scan tool to the machine after it has been sitting overnight (cold engine).

2. 2

   Read the live data values of all engine temperature sensors (coolant, intake manifold, fresh air, etc.).

3. 3

   Compare values to identify if the first fresh air temperature sensor (B-185) is reading an impossible value compared to the other sensors.

4. 4

   Inspect the wiring harness and the connector leading to the fresh air temperature sensor for chafed wires, corrosion, or loose pins.

1. 1

   Ensure the machine is turned off and the battery disconnect switch is engaged.

2. 2

   Locate the first fresh air temperature sensor.

   Typically mounted in the intake airstream or near the fresh air filter housing.

3. 3

   Disconnect the wiring harness from the sensor and inspect the terminals.

   Clean them with electrical contact cleaner if minor corrosion is present.

4. 4

   Remove the faulty sensor.

   Perform this if the wiring tests good but the sensor reading was proven implausible via the scan tool.

5. 5

   Install the new fresh air temperature sensor and securely reconnect the wiring harness.

6. 6

   Turn the battery disconnect switch back on.

7. 7

   Connect the diagnostic tool, clear the inactive 19197 (F-172-02) fault code from the ECU, and perform a cold start to verify the repair.