GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 Catera 🢒 DTC 🢒 DTC 24 Pass. Pretens Deployment Loop Short to GND

Object Number: 255422 Size: SF
SIR Components
SIR Schematics
Handling ESD Sensitive Parts Notice
SIR Caution
SIR Caution
Handling ESD Sensitive Parts Notice

Circuit Description

The inflatable restraint Sensing and Diagnostic and Seat Belt Pretensioner Module (SDM) performs TURN-ON tests to diagnose critical malfunctions within itself when the ignition switch is turned ON. The SDM monitors the six firing loops to detect leakage currents to ground in the frontal and side air bag inflator module and seat belt pretensioner circuits. Then, the SDM proceeds with the RESISTANCE MEASUREMENT test to measure the deployment loop resistances to ensure they are within their respective normal resistance ranges. Upon passing these tests, and if the energy reserve is charged up, the firing transistors are tested. The SDM then goes into CONTINUOUS MONITORING mode. The SDM service wait time is 1 minute. Refer to On-Vehicle Service for enable/disable procedures.

Conditions for Setting the DTC
    • The ignition is within normal operating voltage range.
    • The measured leakage currents to ground in the passenger seat belt pretensioner deployment loop are above a specified value caused by a short circuit from the passenger seat belt pretensioner deployment loop to ground.

DTC 24 will set once one of these conditions is met. This test is run during the SDM Turn-ON 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 Current DTC 24 to set are no longer existing, History DTC 24 will set. History DTC 24 may be cleared using the scan tool.

Diagnostic Aids

A passenger seat belt pretensioner module circuit short-to-ground or a short circuit between the communication signal return line of the LH or RH inflatable restraint Side Impact Sensor (SIS) can cause an intermittent condition. Inspect CKTs AB900, AB950, XB901 and XB950 carefully for cutting and/or chafing. A careful inspection of the circuits and components indicated on the DTC 24 Table is essential to make sure that the replacement SDM will not be damaged. Also inspect CKTs XB42 and XM430 carefully for cutting and/or chafing.

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 step numbers on the diagnostic table.

  1. This test checks for a damaged or corroded SDM harness connector.

    2.

  2. This test determines whether the malfunction is in CKT AB900 or CKT AB950 in the SIR wiring harness.

    3.

  3. This test determines whether the malfunction is in CKT XB901 or CKT XB950 in the SIR wiring harness.

    4.

  4. This test determines whether the malfunction is in CKT AB900 in the passenger seat pretensioner belt assembly.

    5.

  5. This test determines whether the malfunction is in CKT XB901 in the passenger seat pretensioner belt assembly.

DTC 24 Pass. Pretens Deployment Loop Short to GND

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. Wait one minute until the SDM energy reserve capacitors have discharged.
  3. 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.

    .
  4. Disconnect the 8-way body harness-to-passenger seat connector seat connector C316 from the 8-way passenger seat connector located under the RH front seat track cover.
  5. 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 .
  6. Check for proper connection at terminals 15 and 45 on the SDM harness connector.

Are the terminals damaged or corroded?

--

Go to Step 3

Go to Step 5

3

Use the J 42250 Catera Terminal Repair Kit to repair the SDM harness connector.

Are the repairs complete?

--

Go to Step 4

--

4

Check for proper connection at terminal 15 and terminal 45 on the SDM.

Are the terminals damaged or corroded?

--

Go to Step 6

Go to Step 14

5

Check for proper connection at terminal 15 and terminal 45 on the SDM.

Are the terminals damaged or corroded?

--

Go to Step 6

Go to Step 7

6

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 14

--

7

Use the J 39200 Digital Multimeter to measure the resistance on the SDM harness connector from terminal 45 to terminal 7 (ground).

Is the resistance reading less than the specified value?

OL

Go to Step 8

Go to Step 9

8

Repair the short to ground condition in CKT AB900 or CKT AB950 between the 8-way body harness-to-passenger seat connector C316 and the SDM harness connector.

Is the repair complete?

--

Go to Step 14

--

9

Use the J 39200 Digital Multimeter to measure the resistance on the SDM harness connector from terminal 15 to terminal 7 (ground).

Is the resistance reading less than the specified value?

OL

Go to Step 10

Go to Step 11

10

Repair the short to ground condition in CKT XB901 or XB950 between the 8-way body harness-to-passenger seat connector C316 and the SDM harness connector.

Is the repair complete?

--

Go to Step 14

--

11

  1. Remove the front passenger seat from the vehicle. Refer to Seat Replacement in Seats.
  2. Disconnect the passenger pretensioner orange 2-way integral harness connector
  3. Place the front passenger seat in it's proper position.
  4. Connect the front passenger seat harness connectors.
  5. Use the J 39200 Digital Multimeter to measure the resistance from the passenger pretensioner orange 2-way integral harness connector terminal 1 to ground.

Is the resistance reading less than the specified value?

OL

Go to Step 13

Go to Step 12

12

Use the J 39200 Digital Multimeter to measure the resistance from the passenger pretensioner orange 2-way integral harness connector terminal 2 to ground.

Is the resistance reading less than the specified value?

OL

Go to Step 13

Go to Integrity Check

13
  1. Inspect the passenger seat belt side buckle pretensioner seat harness for damage, cutting or chafing.
  2. Replace the Passenger Seat Belt Side Buckle Pretensioner. Refer to Seat Belt Side Buckle Pretensioner Replacement - Pass. in Seat Belts.

Are the repairs complete?

--

Go to Step 14

--

14

Reconnect all the SIR system components. Ensure all the SIR system components are properly mounted.

Are all the SIR system components reconnected and are all the SIR system components properly mounted?

--

Go to Step 15

--

15

Clear the SIR diagnostic trouble codes.

Are the SIR diagnostic trouble codes clear?

--

Go to SIR Diagnostic System Check

--