| Event Code | ||
|---|---|---|
| Code and Description | Conditions which Generate this Code | System Response |
| E194(2) High Exhaust Temperature | The exhaust temperature that has been calculated by the Electronic Control Module (ECM) is above the trip point temperature. | The engine is derated. The code is logged. |
The activation of this event indicates that a high virtual exhaust temperature has been calculated by the ECM. This temperature is calculated with maps that utilize intake manifold temperature, atmospheric pressure, and engine speed as factors.
High intake manifold air temperature, high altitude operation, and high engine loads can cause the exhaust temperature to increase to a level that may damage the exhaust valves and other components of the exhaust system.
When this event occurs, the ECM derates the engine in order to reduce the exhaust temperature. This helps to protect the components of the exhaust system from damage.
Probable Causes
- Engine operating conditions
- Aftercooler
- Power supply to the atmospheric pressure sensor
Recommended Actions
Engine Operating Conditions
Consider high altitude operation of the engine when you troubleshoot this diagnostic code. High altitude operation can cause the code to be generated. This is normal.
Interview the operator, when possible. Determine if the engine is being operated under heavy load. Ensure that the engine is being operated at the proper engine speed.
Aftercooler
The intake manifold air temperature can increase if the flow through the aftercooler is obstructed. Thoroughly check the aftercooler for obstructions. Ensure that the flow of air or coolant through the aftercooler is adequate.
Power Supply to the Atmospheric Pressure Sensor
If the atmospheric pressure sensor is not being powered by the 5 volt supply, the output of the sensor may float to a value that is interpreted by the ECM as a high altitude condition. The ECM receives the erroneous value of altitude and the ECM derates the engine. Ensure that the 5 volt supply is present at the harness connector for the atmospheric pressure sensor.