Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Control module
The Engine Control Module (ECM) controls the following functions:
- cruise control
- the quantity of fuel based on load and engine speed (rpm)
- the fuel-air mixture corresponding to the signals and fuel trim from the heated oxygen sensors (HO2S)
- variable valve times
- idle speed.
- engine cooling fan (FC)
- the quantity of fuel based on load and engine speed (rpm)
- the fuel-air mixture corresponding to the signals and fuel trim from the heated oxygen sensors (HO2S)
- variable valve times
- idle speed.
- ignition spark
- the quantity of fuel based on load and engine speed (rpm)
- the fuel-air mixture corresponding to the signals and fuel trim from the heated oxygen sensors (HO2S)
- variable valve times
- idle speed.
- knock control, individually for each cylinder
- the quantity of fuel based on load and engine speed (rpm)
- the fuel-air mixture corresponding to the signals and fuel trim from the heated oxygen sensors (HO2S)
- variable valve times
- idle speed.
- sequential multiport fuel injection (SFI) including:
- the quantity of fuel based on load and engine speed (rpm)
- the fuel-air mixture corresponding to the signals and fuel trim from the heated oxygen sensors (HO2S)
- variable valve times
- idle speed.
The control module is in a box in the engine compartment.
The Engine Control Module (ECM) is directly connected to the components and to the other control modules via Controller Area Network (CAN) communication.
The control module checks activations and input and output signals via an integrated diagnostic system. A diagnostic trouble code (DTC) is stored if the control module detects an error. In certain cases the control module replaces the faulty signal with a substitute value.
Any diagnostic trouble codes (DTCs) are stored in the control module memory. The data can be read off using VIDA.
A simple way to check that the engine control module (ECM) is supplied with power is to switch on the ignition. If the warning lamp for emissions (Malfunction indicator lamp (MIL)) comes on the control module is supplied with power.
For further information, also see relevant Signal specifications.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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