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.
EGR System
An EGR system is used to reduce oxides of nitrogen (NOx) emissions from vehicle exhaust gases. Exhaust gas is partially recirculated from an exhaust port in cylinder head into the intake manifold port below fuel injection mixer. The EGR system is controlled by the ECU and consists of an EGR control solenoid valve and EGR control valve. See Fig 1 .
The ECU monitors engine speed and coolant temperature. When conditions are met, the ECU de-energizes the EGR solenoid valve. When solenoid is de-energized, EGR control valve is opened (aided by ported vacuum) and EGR flow occurs.
When EGR solenoid is energized by ECU, control valve closes due to combined forces of ported pressure and turbocharged pressure.
The EGR flow is suspended during engine idle and wide open throttle operation. The ECU does not allow EGR flow if engine conditions do not meet the predetermined standard.
Use the Manual With the Right Hardware
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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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