For 1990-2009 cars
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 driver seat belt pretensioner deployment loop are above a specified value caused by:

- | A short circuit from the driver seat belt pretensioner deployment loop to ground.

- | A short circuit between the driver seat belt pretensioner deployment loop and the communication signal return line of the LH or RH inflatable restraint Side Impact Sensor (SIS).

DTC 14 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 14 to set are no longer existing, History DTC 14 will set. History DTC 14 may be cleared using the scan tool.

### Diagnostic Aids

A driver 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 AM900 (AM950 if vehicle has side air bags) and CKT XM901 (XM950 if vehicle has side air bags) carefully for cutting and/or chafing. A careful inspection of the circuits and components indicated on the DTC 14 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 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 .

### 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. This test determines whether the malfunction is in CKT AM900 or AM950 in the SIR wiring harness.

3. This test determines whether the malfunction is in CKT XM901or XM950 in the SIR wiring harness.

4. This test determines whether the malfunction is in CKT AM900 in the driver seat belt pretensioner wiring harness.

5. This test determines whether the malfunction is in CKT XM901 in the driver seat belt pretensioner wiring harness.

#### DTC 14 Driver Pretensioner Deployment Loop Short to Ground

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-driver seat connector seat connector C315 from the 8-way driver seat connector located under the LH 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 8 and 9 on the SDM harness connector.

Are the terminals 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 8 and terminal 9 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 6 | Go to Step 14
5 | Check for proper connection at terminal 8 and terminal 9 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 8 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 AM900 or CKT AM950 between the 8-way body harness-to-driver seat connector C315 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 9 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 XM901 or XM950 between the 8-way body harness-to-driver seat connector C315 and the SDM harness connector. Is the repair complete? | -- | Go to Step 14 | --
11 |

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

Is the resistance reading less than the specified value?

OL

Go to Step 12

Go to Step 13

12 | Use the J 39200 Digital Multimeter to measure the resistance from the driver 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 driver seat belt side buckle pretensioner seat harness for damage, cutting or chafing.
2. Replace the Driver Seat Belt Side Buckle Pretensioner. Refer to Seat Belt Buckle Pretensioner Replacement - LH 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 | --