Scan Tool Does Not Communicate With Keyword Data Line
SCAN TOOL DOES NOT COMMUNICATE WITH KEYWORD DATA LINECIRCUIT 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:
- Electronic brake control module (EBCM)
- Engine control module (ECM)
- Transmission control module (TCM)
DIAGNOSTIC AIDS
- If the malfunction is intermittent, check for poor connections at the suspect module. Wiggling the harness wiring may help in locating the fault.
- Diagnostic trouble codes (DTCs) may be set do to this symptom and during this diagnostic procedure. Complete the diagnostic procedure in order to ensure all the DTCs are diagnosed and cleared from memory.
TEST
