CTS V8-5.7L VIN P (2004)
Information Bus: Symptom Related Diagnostic Procedures
Scan Tool Does Not Communicate With Keyword Data Line
SCAN TOOL DOES NOT COMMUNICATE WITH KEYWORD DATA LINE
CIRCUIT DESCRIPTION
The Keyword protocol utilizes a single wire bi-directional data line between the modules and the scan tool. The message structure is a request and
response arrangement. Keyword serial data is used for scan tool diagnostics only. The modules do not exchange data on this circuit.
The following modules are connected to the Keyword serial data circuit:
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Engine Control Module (ECM)
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Transmission Control Module (TCM) w/M82
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Headlamp Assembly-LF w/export
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Headlamp Assembly-RF w/export
TEST
Steps 1 - 2