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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Test H: No Module/Network Communication

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


H1-H2:






H3-H4:






Normal Operation
The diagnostic tool connects to the data link connector (DLC) C251 to communicate with the standard corporate protocol (SCP), controller area network (CAN), and the international standards organization (ISO) 9141 communication networks. If communication cannot be established, the diagnostic tool and the DLC C251 must be checked for damage. If the diagnostic tool and the DLC C251 are OK, circuit 693 (OG) must be checked for voltage and ground circuits 57 (BK), and 570 (BK/WH) must be checked for an open condition.

Possible Causes
- fuse
- DLC C251
- diagnostic tool
- circuit 57 (BK) open circuit
- circuit 570 (BK/WH) open circuit
- circuit 693 (OG) open or short to ground