CLAAS 777Ch – ENG A15: Fresh Air Intake Temperature Averagely High

The engine control module has detected that the fresh air intake temperature is abnormally high. Because hotter air is less dense, this condition affects the air-fuel mixture and combustion efficiency. To protect the engine, the ECM automatically reduces engine power by 5% per minute until it reaches 80% of its nominal power. Full power is restored at a rate of 5% per minute once the intake temperature returns to a normal operating range.

• Arion 500 series
• Arion 600 series
• Arion 640-510

1. 1

   Inspect the air intake system for blockages, including large intake panels in the bonnet, the engine air filter, and radiator assemblies. Debris such as dust, chaff, and leaves can restrict airflow and lead to increased intake temperatures.

2. 2

   Check the radiator and charge air cooler (intercooler) fins for dirt or debris that could impede heat dissipation.

3. 3

   Check for related fault codes, such as 7779h, which indicates high input voltage from the fresh air intake temperature sensor (B222) and points directly to a sensor or wiring issue.

4. 4

   Visually inspect the fresh air intake temperature sensor (B222) and its wiring harness for damage, corrosion, or loose connections, and check the continuity of the harness linking the component to the control module for short circuits or open circuits.

1. 1

   Address airflow issues

   If any blockages were found in the air intake path or cooling assemblies, remove the obstruction and clean the components thoroughly.

2. 2

   Test the sensor

   Test the fresh air intake temperature sensor (B222) using a multimeter to check resistance at different temperatures against manufacturer specifications, or use an OBD-II scanner to verify live data readings.

3. 3

   Check wiring and connections

   If the sensor tests within specifications, check the wiring between the sensor and the ENG A15 engine module for continuity, short circuits to ground, or short circuits to positive.

4. 4

   Replace the sensor

   If the fresh air intake temperature sensor (B222) is found to be faulty, replace it.

5. 5

   Clear fault codes

   After the repair, clear all related fault codes from the engine module's memory and operate the tractor to ensure the fault does not reappear.