Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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EGR Valve: Testing and Inspection




1. Manually actuate valve by pushing on diaphragm with finger.
2. Ensure spring resistance is present and that diaphragm moves freely with no sticking or binding. Before replacing EGR control valve, check intake air and control systems.
3. Warm engine to operating temperature and run at idle.
4. Connect vacuum pump to valve and apply vacuum.
5. Ensure engine runs roughly or stalls at vacuum of more than 1.6---2.4 inches Hg.
6. If engine does not perform as described, replace EGR control valve.