W 3500 L4-5.2L DSL Turbo (2006)
Engine Control Module: Description and Operation
Engine Control Module (ECM) Description
Engine Control Module (ECM) Service Precautions
Important:
Symbol (1) indicates that important procedural information is contained in the Workshop Manual. Refer to this manual before starting any work. Follow
the instructions exactly to avoid equipment damage and personal injury.
Symbol (2) warns you of an electric shock hazard. To avoid shock and possible serious injury, do not touch the terminals.
The engine control module (ECM) is designed to withstand normal current draws associated with vehicle operation. Avoid overloading any circuit.
When testing for opens and shorts, do not ground or apply voltage to any of the ECM circuits unless instructed to do so. In some cases, these circuits
should only be tested using a digital multimeter (DMM). The ECM should remain connected to the ECM harness.
The engine control module (ECM) is located on the chassis frame side near the transmission. The ECM controls the following:
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The fuel supply control
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The fuel injection timing control
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The exhaust gas recirculation (EGR) control
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The preheating control (glow control)
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The on-board diagnostics for engine control
The ECM constantly observes the information from various sensors. The ECM controls the systems that affect vehicle performance. The ECM performs
the diagnostic function of the system. The ECM can recognize operational problems, alert the driver through the malfunction indicator lamp (MIL), and
store diagnostic trouble codes (DTCs). DTCs identify the system faults to aid the technician in making repairs.
