U1161

Refer to Data Link Connector (DLC) Schematics: Simple Bus Interface (SBI).

CIRCUIT DESCRIPTION
The simple bus interface (SBI) data line communicates information between the door modules. Each module connected to the SBI is assigned a recognition code, or address. This code is used in order to identity which modules are communicating. Modules communicate with each other by periodically sending State Of Health (SOH) messages. When the ignition switch is in RUN, each module communicating on the SBI sends an SOH message every 2 seconds. This ensures that the system is operating properly. When the Passenger Door Module (PDM) stops communicating the SOH messages that is normally sent disappears. The Driver Door Module (DDM) which expects to receive that message detects the absence of the message and sets DTC U1161.

CONDITIONS FOR RUNNING THE DTC
^ The DDM does not receive an SOH message back from the PDM.
^ The DTC only sets if U1300 or U1301 are not current.

ACTION TAKEN WHEN THE DTC SETS
^ DTC U1161 is stored in the DDM.
^ The DDM uses the default values for the initialization data.
^ This DTC does not cause a driver warning message to appear.

CONDITIONS FOR CLEARING DTC
This DTC clears (status changes from current to history) under any of the following conditions:
^ The DDM detects an SOH message from the PDM.
^ At each ignition cycle.

DIAGNOSTIC AIDS
^ DTC module U1161 does not normally represent a failure within the module.
^ If the DTC is a history DTC, the problem may be intermittent.