Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptor
DTC U1241: Lost Communication With Scan ToolCircuit/System Description
The passenger presence system (PPS) monitors itself for faults and will set/flash DTCs if a fault is detected. The PPS communicates with the inflatable restraint sensing and diagnostic module (SDM) via non class 2 communications. When the SDM receives input from the PPS that a PPS fault has occurred, the SDM will request the instrument panel cluster (IPC) to illuminate the AIR BAG indicator located on the IPC. To determine what DTCs have been set by the PPS, the Tech 2 is used to command the SDM to request the PPS to flash the DTCs using the PASSENGER AIR BAG ON/OFF indicators located on the rearview mirror. The Tech 2 sends a string of commands to the SDM that allows the SDM to communicate with the PPS module and initiate the flashing of the DTCs. When the Tech 2 has completed sending the commands, the PPS will begin flashing any current or history DTCs that the system has stored. When the SDM no longer receives commands from the Tech 2, the SDM mistakes this as a communication fault and sets DTC U1241. DTC U1241 will set when the Tech 2 is used to flash DTCs from the PPS or after the PPS has been rezeroed. DTC U1241 does not indicate a system malfunction and will not cause any warning indicators to illuminate. When DTC U1241 sets, cycle the ignition and use the scan tool to clear the code, no further diagnosis is necessary.
Conditions for Running the DTC
Ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
DTC will set when the Tech 2 is used to flash DTCs from the PPS or after the PPS has been rezeroed.
Action Taken When the DTC Sets
No system malfunction and will not cause any warning indicators to illuminate.
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
SIR System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Ignition ON, clear DTC with a scan tool, if DTC resets, replace the SDM.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for SDM replacement, setup, and programming
