GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Catera 🢒 Restraints 🢒 SIR 🢒 DTC 97 ONSTAR DCO Link Open or Short to Voltage

Object Number: 255430 Size: SF
SIR Components
SIR Schematics
SIR Caution
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

Circuit Description

The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) performs tests to diagnose critical malfunctions within itself when the ignition switch is turned ON. The SDM is hard-wired to the Body Control Module (BCM) CKT XY999. After the ignition is turned ON , the SDM sends fixed frequency pulses to the BCM. In the event of a collision involving air bag deployment, the SDM sends higher frequency pulses to the BCM, which in turn sends a Class 2 message to the Vehicle Interface Unit (VIU). The VIU transmits a DCO signal to OnStar via the vehicle's cellular telephone. The SDM monitors CKT XY999 to detect leakage currents to voltage and open circuits in the Deployment Commanded (DCO) link to the BCM. The SDM service wait time is 1 minute. Refer to On-Vehicle Service for enable/disable procedures.

Conditions for Setting the DTC

The following conditions can cause DTC 97 to set:

    • A short circuit between CKT XY999 and system voltage.
    • A open circuit condition in CKT XY999 between the SDM and the BCM.

This test is run during the SDM Turn-ON and Continuous Monitoring tests.

Action Taken When the DTC Sets
    • The SDM sets a Diagnostic Trouble Code.
    • The SDM turns ON the AIR BAG warning lamp.

Conditions for Clearing the DTC

Current and History DTC codes must be cleared using a scan tool Clear DTC Information command. If the circuit fault has been successfully repaired and the conditions which caused the DTC to set are no longer existing, the DTC may be cleared using the scan tool.

Diagnostic Aids

A short circuit to a voltage source in the DCO circuit CKT XY999 can set this DTC. Inspect CKT XY999 carefully for cutting and/or chafing. A careful inspection of the circuit and components indicated on the DTC 97 Table is essential to make sure that the SDM and/or BCM will not be unnecessarily replaced.

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 Intermittents and Poor Connections . When a wire, connector or terminal repair is requested, use J-38125 Terminal Repair Kit and refer to Wiring Repair .

Test Description

The numbers below refer to the step numbers on the diagnostic table:

  1. This test determines if the BCM harness connector C1 is damaged.

    2.

  2. This test checks for proper contact or corrosion of the BCM terminals.

    3.

  3. This test checks for proper contact or corrosion of the SDM harness connector.

    4.

  4. This test checks for an open circuit or high resistance condition in CKT XY999.

    5.

  5. This test checks for a short to voltage condition in CKT XY999.

    6.

  6. This test determines if the fault is internal to the BCM or the SDM.

DTC 97 ONSTAR DCO Link Open or Short to Volatge

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the Body Control Module (BCM) harness connector from the BCM. Refer to Body Control Module Replacement in Body Control System.
  3. Check for proper connection at terminal A05 on the body harness connector C1.

Is the terminal damaged or corroded?

--

Go to Step 3

Go to Step 5

3

Replace the body harness.

Are the repairs complete?

--

Go to Step 4

--

4

Check for proper connection at terminal A05 on the BCM.

Is the terminal damaged or corroded?

--

Go to Step 6

Go to Step 17

5

Check for proper connection at terminal A05 on the BCM.

Is the terminal damaged or corroded?

--

Go to Step 6

Go to Step 7

6

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Are the repairs complete?

--

Go to Step 17

--

7

  1. Disconnect the negative battery cable. Refer to

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

    .
  2. Disconnect the inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .
  3. Check for proper connection at terminal 40 on the SDM harness connector.

Is the harness connector damaged or corroded?

--

Go to Step 8

Go to Step 10

8

Replace the IP harness.

Are the repairs complete?

--

Go to Step 9

--

9

Check for proper connection at terminal 40 on the SDM.

Are the terminals damaged or corroded?

--

Go to Step 11

Go to Step 17

10

Check for proper connection at terminal 40 on the SDM.

Is the terminal damaged or corroded?

--

Go to Step 11

Go to Step 12

11

Replace the inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .

Are the repairs complete?

--

Go to Step 17

--

12

  1. Zero the J 39200 J 39200.
  2. Measure the resistance from the BCM harness connector C1 terminal A05 to terminal 40 of the SDM harness connector.

Is the resistance reading within the specified values?

0-0.5 ohms

Go to Step 14

Go to Step 13

13

Repair the high resistance condition in CKT XY999.

Are the repairs complete?

--

Go to Step 17

--

14

  1. Reconnect the negative battery cable.
  2. Turn the ignition switch to the ON position.
  3. Measure the voltage from the SDM harness connector terminal 40 to terminal 7 (ground).

Is the measured voltage less than the specified value?

1 V

Go to Step 16

Go to Step 15

15
  1. Turn the ignition switch to the OFF position
  2. Repair the short to B+ condition in CKT XY999.

Are the repairs complete?

--

Go to Step 17

--

16

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the negative battery cable. Refer to

    Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

    .
  3. Reconnect the BCM body harness connector to the BCM.
  4. Reconnect the SDM harness connector to the SDM.
  5. Reconnect the negative battery cable.
  6. Connect a scan tool to the DLC.
  7. Turn the ignition switch to the ON position.
  8. Perform the Body Control Module (BCM) Diagnostic System Check. Refer to Diagnostic System Check - Body Control System .
  9. If the BCM Diagnostic System Check directs that the BCM must be replaced, replace the BCM. Refer to Body Control Module Replacement .

Has the BCM been replaced?

--

Go to Step 17

Go to Integrity Check

17

Reconnect all the SIR components, make sure all the components are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to Step 18

--

18

Clear all the SIR DTCs.

Have all the DTCs been cleared?

--

Go to SIR Diagnostic System Check

--