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
Voltage Signal: Description and Operation
^
The coil tach signal is a function of the ignition diagnostic monitor (IDM) signal sent to the ECA computer from the EDIS (
ignition system) module.
^
This signal provides the computer with engine rpm information as well as driving the vehicle instrument tachometer and/or a test tachometer for diagnosis.