The Electronic Control Module (ECM) is in the engine compartment. The ECM is the control center of the engine controls system. The ECM controls the following components:
The ECM constantly monitors the information from various sensors and other inputs, and controls the systems that affect the vehicle performance and the emissions. The ECM also performs diagnostic tests on various parts of the system. The ECM can recognize operational problems and alert the driver via the MIL. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.
The engine control module (ECM) can supply 5 volts or 12 volts to the various sensors or switches. This is done through pull-up resistors to the regulated power supplies within the ECM. In some cases, even an ordinary shop voltmeter will not give an accurate reading because the resistance is too low. Therefore, a DMM with at least 10 megaohms input impedance is required in order to ensure accurate voltage readings.
The ECM controls the output circuits by controlling the ground or the power feed circuit through the transistors or a device called an output driver module.
Removal & Installation
- Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
- Record the preset radio stations.
- Turn the ignition OFF.
- Disconnect the negative battery cable.
- Remove the left front fender.
- Remove the windshield washer solvent container.
- Release the Engine Control Module (ECM) bracket upper and lower retaining tabs using a small screwdriver or other suitable tool.
- Remove the ECM from the bracket by lifting upward after releasing the tabs.
- Disconnect the engine wiring harness electrical connectors from the ECM.
- Connect the engine wiring harness electrical connectors to the ECM.
- Slide the ECM into the bracket.
- Push down on the ECM until the upper and lower retaining tabs snap into place.
- Connect the negative battery cable.
- Install the windshield washer solvent container.
- Install the left front fender.
- Reset the clock and preset radio stations.
- If a new ECM was installed, the ECM must be programmed.
Test the voltage and ground circuits to the control module for the following:
If all circuits test normal, suspect the ECM.
NOTEThe replacement control module must be programmed.