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.
Catalytic Converter System Description - Overview
The warm up three way catalytic converter (WU-TWC) and the under-floor three way catalytic converter (Under-floor TWC) convert hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx) in the exhaust gas to carbon dioxide (CO 2), nitrogen (N 2), and water vapor. The WU-TWC is attached directly under the cylinder head that is integrated into the exhaust manifold.
WU-TWC (Attached to the cylinder head)
UNDER-FLOOR TWC
NO RELATED
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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.