For the Engine Data Line (EDL) Diagram, see Figure “Engine Data Line Diagram” . Figure 1. Engine Data Line Diagram Section 27.1.1 Circuit Functions The ECM is programmed with two shift schedules — the Closed Throttle Mode and the Wide Open Throttle Mode. Closed Throttle Mode is for situations with moderate engine load. ECM pin… Read More »
The Engine Coolant Temperature (ECT) sensor is a thermistor type sensor that has a variable resistance that changes when exposed to different temperatures. When interfaced with the ECM it produces a 0 to 5 volt analog signal that indicates temperature. See Figure “Engine Coolant Sensor Function Diagram” . Figure 1. Engine Coolant Sensor Function Diagram… Read More »
The purpose of the Engine Coolant Level (ECL) monitoring system is to signal the driver in the event of a low coolant situation. Depending on the programming of the control module it is also capable of shutting off the engine to prevent damage to the engine due to low coolant level. See Figure “Engine Coolant… Read More »
The Engine Crank Inhibit (ECI) feature of the ECM is used to control the operation of the cranking motor. The ECM prevents the cranking motor from being engaged when the engine is running. The transmission neutral safety switch or clutch switch will prevent the cranking motor from being engaged when the transmission is in gear… Read More »
Follow these procedures to diagnose and correct the Electronic Foot Pedal Assembly and Idle Validation Sensor. Section 23.1.1 Signal Functions The accelerator position sensor is a potentiometer type sensor that, when supplied with a 5 volt reference signal from the ECM provides a linear analog voltage signal that indicates the driver’s demand for power.… Read More »
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 »