U1192

Circuit Description
The class 2 serial data line is used in order to communicate information between the modules. Each module connected to the serial data line is assigned a recognition code (address). This code is used in order to identify which modules are communicating. Modules communicate with each other by periodically sending State of Health (SOH) messages. When the ignition switch is in the RUN position, each module communicating on the serial data line sends an SOH message every 2 seconds in order to ensure that the system is operating properly. When the Passlock(TM) sensor stops communicating on the class 2 serial data line (if the Passlock (TM) sensor loses power or ground) the SOH message that is normally sent on the serial data line every 2 seconds is not received by the instrument cluster, the instrument cluster sets an internal DTC U1192 that is associated with the loss of SOH of the Passlock (TM) sensor that is no longer communicating on the class 2 Serial Data line.

Conditions for Setting the DTC
- The instrument cluster does not receive an SOH message back from the PasslockTM sensor for 5 seconds.
- This DTC only sets if DTC U1300 or DTC U1301 is not current in the instrument cluster memory.

Action Taken When the DTC Sets
- DTC U1192 is stored in the instrument cluster memory.
- The instrument cluster uses the default values for the data that are normally received from the PasslockTM sensor.
- This DTC does not cause a driver warning message to appear.

Conditions for Clearing the DTC
This DTC clears (status changes from current to history) under any of the following conditions:
- The instrument cluster detects an SOH message from the PasslockTM sensor.
- The ignition switch is cycled.
- A history DTC clears after 50 consecutive ignition cycles if the conditions for setting the DTC are no longer present.
- Use a scan tool.
- Use the instrument cluster on-board clearing DTCs feature.

Diagnostic Aids
- Instrument cluster DTC U1192 does not normally represent a failure within the instrument cluster.
- When loss of class 2 serial data communication DTCs (DTCs with the letter U as the prefix) are stored as history DTCs know all of the possible serial data DTCs set in each module before diagnosing the serial data line.
- If DTC U1192 is stored in the instrument cluster memory,inspect for the same DTC stored in other modules capable of storing this DTC. The Data Link Connector (DLC) circuit description provides a chart that indicates which modules may set DTC U1192.
- If the DTC is a history DTC, the problem may be intermittent.

Step 1:

Steps 2 - 5:

Test Description
The numbers below refer to the step numbers on the diagnostic table:
1. Perform the Instrument Cluster Diagnostic System Check before continuing with the diagnosis of this DTC.
2. DTC U1192 is the result of loss of communication with the PasslockTM sensor. The instrument cluster is the only module that may set DTC U1192.
5. Clear all DTCs after the repair procedure is complete.