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)

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Test O: No Module/Network Communication - No Power To The Diagnostic Tool

PINPOINT TEST O: NO MODULE/NETWORK COMMUNICATION - NO POWER TO THE DIAGNOSTIC TOOL


O1-O4:






O4 Continued:






Normal Operation
The diagnostic tool is connected to the data link connector (DLC) C251 to communicate with the high speed controller area network (CAN), medium speed CAN, and international standards organization (ISO) 9141 communications networks. If communication can not be established, the diagnostic tool and the DLC C251 must be checked for damage. If the diagnostic tool and the DLC C251 are OK, circuits 40 (LB/WH), 1203 (BK/LB), and 1205 (BK) must be checked for an open condition.

Possible Causes
- fuse
- DLC C251
- diagnostic tool
- circuit 40 (LB/WH) open
- circuit 1203 (BK/LB) open
- circuit 1205 (BK) open