Diagnostic Procedure
- DTC U1064 does not necessarily represent an MSM failure. If DTCs are history, check DTCs each module may set on class 2 data line before diagnosing class 2 data line problem.
- Clear all DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES (DTCS) under SELF-DIAGNOSTICS. Cycle ignition. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES (DTCS) under SELF-DIAGNOSTICS. If no DTCs exist, recheck system operation.
- If multiple DTCs exist, check for intermittent short to ground in circuit No. 1807 (Purple wire) between MSM and other modules on class 2 serial data line.
- If DTC is current, use scan tool to establish communication with PZM. If communication cannot be established, see BODY CONTROL MODULE article. If communication can be established, replace MSM.
- If DTC is history, check for intermittent open in circuit No. 1807 (Purple wire) between MSM and other modules on class 2 serial data line.