The ECM requires a 12 volt source of power to perform its functions. It receives this operating power directly from the vehicle batteries via the ECM relay contacts each time the ignition key switch is turned to the on position. Turning the ignition key switch ON causes the ECM to provide an internal ground to… Read More »
The ECM monitors and controls engine/vehicle operation and performance, enables vehicle features such as PTO and cruise control to function, communicates engine/vehicle information to the instrument cluster transmission (on vehicles equipped with electronically controlled transmissions) and diagnostic/programming tools. For the ECM, see Figure “Electronic Control Module” . Figure 1. Electronic Control Module Section 21.1.1 Fault… Read More »
Follow these procedures to diagnose and correct faults with the Change Oil Lamp. Section 20.1.1 System Functions The amber Change Oil Lamp will be illuminated when a customer programmable service interval has been exceeded. These limits may be set up in terms of vehicle miles, hours or calculated fuel consumption. These service interval limits may… Read More »
Follow these procedures to diagnose and correct Camshaft Position Sensor (CMP) faults. Section 19.1.1 Signal Functions The CMP sensor is a Hall Effect type sensor that generates a digital frequency as windows on the timing disk pass through its magnetic field. The frequency of the windows passing by the sensor as well as the width… Read More »
The service brake circuit function is to signal the ECM when the brakes are applied. This information is used to disengage the cruise control and PTO functions. The signal is also used for ECM control of the Vehicle Retarder and exhaust brake enabling. The brake signal will interrupt the Cold Ambient Protection feature and will… Read More »
The BARO (Barometric Pressure) sensor is a variable capacitance sensor that, when supplied with a 5 volt reference signal from the ECM, produces a linear analog voltage signal that indicates pressure. For the Barometric Pressure Sensor function diagram, See Figure “Barometric Pressure Sensor Function Diagram” . Figure 1. Barometric Pressure Sensor Function Diagram Timing Control… Read More »
The signal functions include the Data Communication Link and the ATA Diagnostic/Programming Link. See Figure “ATA Communications Function Diagram” . Figure 1. ATA Communications Function Diagram Data Communication Link — The signal is a 0 to 5 volt variable width square wave form signal that enables communication between the electronic service tool (EST) and the… Read More »
Follow these procedures to diagnose problems with the sensor or actuator circuits. Section 15.1.1 Basic Procedure The basic diagnostic procedure recommended for most sensor and actuator circuits is to disconnect the harness at the connector and inspect for corrosion, bent pins, spread pins, or any condition that could cause a loose or intermittent connection. See… Read More »
For location of sensors, see Figure “Sensor and Actuator Locations on the Engine” , and see Figure “Sensor and Actuator Locations on the Engine” . 1. Injection Pressure Regulator 4. Injection Control Pressure Sensor 2. Engine Oil Temperature Sensor 5. Engine Oil Pressure Sensor 3. Manifold Absolute Pressure Sensor Figure 1. Sensor and Actuator… Read More »
A description of the types of sensors follows. Section 6.2.1 Thermistor A thermistor is a type of sensor that changes its electrical resistance with temperature to which it is being exposed. The electrical resistance of the thermistor decreases as temperature increases and increases as temperature decreases. The sensor, in conjunction with a current limiting resistor… Read More »