Code 75 - Serial Communication Failure: Notes

Detects if no communication is present with electronic instrument cluster via the serial data link. Code 75 can set anytime after ABS initialization. A malfunction exists if a message from instrument cluster is not received within 7 seconds. A serial communication failure does not allow proper warning light commands to be sent to instrument cluster, setting code.

NOTE: Test numbers refer to numbers on diagnostic chart. Use only 10-megohm (minimum) DVOM for all voltage and resistance tests. For identification of circuits and terminals referenced in charts and text, see WIRING DIAGRAM .

Fig 1: Code 75 Diagnostic Flow Chart

Courtesy of GENERAL MOTORS CORP.

Checks if electronic instrument cluster is operating properly.
Checks if communication between EBCM and instrument cluster is possible.