GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Seville 🢒 Restraints 🢒 SIR 🢒 DTC B1163 Loss of Serial Data-No Lamp Response

Circuit Description

When the ignition switch is first turned to ON, the instrument cluster (IPC) flashes the AIR BAG warning lamp 7 times. If no SIR DTCs are present, the inflatable restraint sensing and diagnostic module (SDM) then commands the IPC to turn the AIR BAG warning lamp OFF by sending a message over the class 2 serial data line. The IPC then returns a message to the SDM that the AIR BAG warning lamp is OFF. For more detailed information about the data lines, refer to Data Link Connector Replacement in Wiring Systems.

Conditions for Setting the DTC

If the SDM receives the wrong response from the IPC after sending the AIR BAG warning lamp message 6 times, the SDM will set DTC B1163. A loss of State Of Health (SOH) DTC U1096 or DTC U1255 is also set. The test for DTC B1163 is run Asynchronously during Continuous Monitoring.

Action Taken When the DTC Sets

The SDM sets a Diagnostic Trouble Code (DTC).

Conditions for Clearing the MIL/DTC

The DTC will clear when one of the following conditions is met:

  1. Current DTC
    2. 1.1. The ignition is turned OFF.
    1.2. The SDM receives the correct IPC message response over the class 2 serial data line.
  2. History DTC
    3. 2.1. You issue a scan tool Clear DTCs command.
    2.2. Once 250 malfunction free ignition cycles have occurred.

Diagnostic Aids

The following failures could cause a history DTC B1163 to set.

    • The IPC lost B+ or ground with the ignition switch in the ON position.
    • An intermittent short to B+ or ground in CKT 1807 class 2 serial data line.
    • An intermittent open in CKT 1807 class 2 serial data line.

The State Of Health (SOH) DTCs will likely be set with DTC B1163 when communication is lost between the IPC and the SDM. Check that the IPC is functioning properly. Use the IPC loss of communication DTC diagnostic information. Refer to DTC U1096 Loss of Communications with IPC in Body Control System.

When measurements are requested in this table, use J 39200 Digital Multimeter with the correct terminal adapter from J 35616 Connector Test Adapter Kit. When a check for proper connection is requested, refer to General Electrical Diagnosis Procedures in Wiring Systems. When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .

CAUTION: Be careful when you handle a sensing and diagnostic module (SDM). Do not strike or jolt the SDM. Before applying power to the SDM:

   • Remove any dirt, grease, etc. from the mounting surface
   • Position the SDM horizontally on the mounting surface
   • Point the arrow on the SDM toward the front of the vehicle
   • Tighten all of the SDM fasteners and SDM bracket fasteners to the specified torque value
Failure to follow the correct procedure could cause air bag deployment, personal injury, or unnecessary SIR system repairs.

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

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Go to Step 2

Go to SIR Diagnostic System Check

2
  1. Malfunctions within the class 2 serial data line will set this DTC. These malfunctions are addressed in the SIR Diagnostic System Check. Failure to properly perform the SIR Diagnostic System Check may result in misdiagnosis.
  2. Turn the ignition switch to ON.
  3. Clear the SIR DTCs. Refer to Diagnostic Trouble Code (DTC) Clearing in Wiring Systems.
  4. Request the SIR DTC Display.

Is DTC B1163 set?

--

Go to Sensing and Diagnostic Module Integrity Check

Go to SIR Diagnostic System Check