OBDII Automotive Articles - How does OBDII work? - 60,544 Views

How does OBDII work?

What How does OBDII work? Means:

The Engine Control Module (ECM) or Powertrain Control Module (PCM) continuously monitors the engine for conditions that can cause an increase in tailpipe emissions. If the ECM or PCM detects a potential problem with the engine, a warning light called a "malfunction indicator light" (MIL) on the dashboard is illuminated to alert the driver of a problem. This light is usually identified by the words "Check Engine," "Service Engine Soon," or the word "Check" along with an engine symbol. The ECM or PCM will also store a Diagnostic Trouble Code" (DTC) in the computer's memory. This DTC can be retrieved with a code reader device to help diagnose problems with the vehicle.

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How does OBDII work?