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

Initial Inspection and Diagnostic Overview


Input signals for sensors are monitored by the computer (ECU). The computer stores the operating conditions of these sensors in its memory and the operating conditions of these conditions can be ``read'' from the memory, using a voltmeter. The malfunction is stored in the computers memory by power supplied directly from the battery, therefore cannot be erased by turning the ignition key ``Off.'' However, if the battery ground cable is disconnected, then malfunction will be erased.
There are nine malfunction codes including one for a normal reading, that can be stored in memory. The codes are as follows:
1. Oxygen sensor.
2. Crankshaft angle sensor.
3. Air flow sensor (AFS).
4. Atmospheric pressure sensor.
5. Throttle position sensor (TPS).
6. Motor position sensor.
7. Engine coolant temperature sensor.
8. No. 1 cylinder TDC sensor.