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

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

Knock Sensor: Service and Repair



Measurement Unit, Combustion (740)

To remove
1. Unplug the connector to CDM.






2. Remove CDM.

To fit
1. Fit CDM.






2. Plug in the connector to CDM.