For the Voltage Reference Circuits (VREF) function diagram, see Figure “Voltage Reference Circuits Function Diagram” . 1. Engine Oil Pressure Sensor 5. Accelerator Position/Idle Validation 2. Camshaft Position Sensor 6. Barometric Pressure Sensor 3. Injection Control Pressure Sensor 7. Manifold Absolute Pressure Sensor 4. ECM Figure 1. Voltage Reference Circuits Function Diagram The… Read More »
For the Vehicle Speed Sensor (VSS) function diagram, see Figure “Vehicle Speed Sensor Function Diagram” . Figure 1. Vehicle Speed Sensor Function Diagram Section 45.1.1 Signal Function Transmission tail-shaft speed is detected by a magnetic pickup mounted on the transmission that senses the rotation of a 16–toothed gear installed on the rear of the transmission.… Read More »
For the Vehicle Retarder function diagram, see Figure “Vehicle Retarder Function Diagram” . 1. Engine Oil Pressure Sensor 5. Accelerator Position/Idle Validation 2. Camshaft Position Sensor 6. Barometric Pressure Sensor 3. Injection Control Pressure 7. Manifold Absolute Pressure Sensor 4. ECM Figure 1. Vehicle Retarder Function Diagram On engines or vehicles equipped with… Read More »
For the Two Speed Axle (TSA) circuit function diagram, see Figure “Two Speed Axle Circuit Function Diagram” . The ECM is programmed with the high and low rear axle ratios. The ratios are used to calculate the speedometer signal, depending on which mode the switch is in. The ECM uses the high ratio unless voltage… Read More »
For the tachometer input circuit function, see Figure “Tachometer Input Circuit Function” . The ECM provides an output for a remote tachometer with a 0 — 12 volt digital signal that indicates engine speed. The frequency sent by the ECM is 1/5th of the actual engine r/min. Figure 1. Tachometer Input Circuit Function Section 42.1.1… Read More »
For the self test input switch function diagram, see Figure “Self Test Input Switch Function Diagram” . Figure 1. Self Test Input Switch Function Diagram Section 41.1.1 Self Test Input Switch The Self Test Input (STI) switch runs the Key On Engine OFF (KOEO) Standard Tests. (STI is sometimes referred to as the EST.) Faults… Read More »
Speed Control command Switches (SCCS) include cruise control, PTO, and the hand throttle system, see Figure “Speed Control Command Switches Function Diagram” . Figure 1. Speed Control Command Switches Function Diagram Section 40.1.1 Cruise Control The ECM will control the engine speed to maintain a constant road speed with cruise control. Depressing the set switch… Read More »
The purpose of Radiator Shutter Enable (RSE) circuit is to provide control to open or close the radiator shutters (energize or de-energize a solenoid). The purpose of this device is to keep the engine warm during cold weather operation. When the ignition switch is in the ON position, power is available to the shutter solenoid.… Read More »
The purpose of the Remote Accelerator Pedal Sensor (RPS) is to allow an operator to adjust engine speed from a remote location. The RPS functions similar to the Accelerator Position Sensor. For the RPS function diagram, see Figure “Remote Accelerator Pedal Sensor Function Diagram” . Figure 1. Remote Accelerator Pedal Sensor Function Diagram Note: The… Read More »
The red Oil and Water Lamp (OWL) and the Engine Alarm Buzzer are intended to be turned on when conditions are present that will cause impending damage to the engine. The level of protection is dependent upon which Engine Warning and Protection System (EWPS) is turned on in the ECM. When the ignition switch is… Read More »