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| Illustration 1 | g00897891 |
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C18 Left side view (1) Inlet manifold pressure sensor (2) Unit injector connector (3) Inlet manifold temperature sensor (4) Ground connection for the OEM (5) Speed/timing sensor for the crankshaft (lower left front of engine) (6) Speed/timing sensor for the camshaft (upper left front of engine) (7) Fuel temperature sensor (8) Atmospheric pressure sensor (right side of the fuel filter and left of the oil pressure sensor) (9) Oil pressure sensor (right side of the fuel filter and right of the atmospheric pressure sensor) (10) Turbocharger wastegate solenoid (right side at fuel filter base) | |
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| Illustration 2 | g00909650 |
| (11) Coolant temperature sensor | |
The engine coolant temperature is measured by an electronic sensor that is mounted on the water outlet housing. The signal for the engine coolant temperature sensor is used to modify the engine fueling and the signal is used to modify the engine timing. By modifying the engine fueling and the engine timing, the engine will improve the following conditions: cold start capability and white smoke cleanup. The Engine Control Module (ECM) supplies the coolant temperature sensor with 5.0 ± .5 VDC. The sensor output voltage is 0.5 to 4.5 VDC. The sensor output voltage depends on the engine coolant temperature. Coolant temperature is used in order to indicate the Cold Mode Operation. Coolant temperature is also used for Engine Monitoring.
The fuel temperature is monitored in order to adjust the calculations for the fuel rate. The fuel temperature is monitored for the power correction when the fuel temperatures exceed
The atmospheric pressure sensor is an absolute pressure sensor that measures crankcase pressure. The atmospheric pressure sensor is used to calibrate the other pressure sensors on the engine. The values for these sensors that are communicated over the data link are calculated by subtracting the atmospheric pressure sensor reading. The atmospheric pressure sensor measures pressure from
Inlet Manifold Temperature Sensor
The inlet manifold temperature sensor measures the temperature of the air in the inlet manifold. The ECM monitors the signal for the inlet manifold temperature sensor. The output of the ECM can indicate high inlet manifold air temperature through a relay or a lamp. The inlet manifold temperature sensor will not cause a shutdown of the engine or any horsepower change.
Note: The sensor will be affected by the heat that is conducted from the air in the inlet manifold when the engine is idling, and after the engine is shut off. This warm-up is due to the lack of coolant circulation through the engine. The reading from the sensor for the inlet manifold temperature may be significantly higher than the actual temperature of the air inside the inlet manifold until the inlet manifold cools.
The Inlet manifold pressure sensor provides a signal which corresponds to turbocharger outlet pressure to the ECM. The air/fuel ratio control utilizes the actual engine speed and the turbocharger outlet pressure in order to control the transient smoke level. The ECM can control injection timing and the amount of fuel that is injected. When the throttle is increased and when the engine demands more fuel, the fuel limit is controlled in order to reduce overall smoke levels of the engine exhaust.
The oil pressure sensor is a part of the engine monitoring system. The engine monitoring system is used for all options that are monitored. The oil pressure sensor is an absolute pressure sensor that measures oil pressure in the oil gallery. The oil pressure is communicated over the data link and the oil pressure is displayed by the service tools. The ECM uses the sensor input only if the parameter for the Engine Monitoring is programmed to one of the following functions. "OFF" is no longer an option.
- Warning Mode
- Derate Mode
- Shutdown Mode
The oil pressure sensor measures pressure from
If the ECM does not receive a signal from the primary speed/timing sensor (camshaft), the "DIAGNOSTIC" lamp will indicate a diagnostic fault code which will be logged in the ECM memory.
If the ECM does not receive a signal from the primary speed/timing sensor (camshaft), the ECM will read the signal from the secondary speed/timing sensor (crankshaft). The ECM continually checks in order to determine if there is a signal from both sensors. If either sensor fails, the faulty sensor should be replaced.
Intermittent failure of the sensors will cause erratic engine control.
The coolant level sensor is installed by the OEM. This sensor is a programmable parameter and this sensor may be protected by a customer password.
Accelerator Pedal Position Sensor
The accelerator pedal position sensor is an electronic sensor that is connected to the accelerator pedal. The accelerator pedal position sensor sends a Pulse Width Modulated Signal to the ECM.