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 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 and system voltage in the frontal and side air bag inflator module and seat belt pretensioner circuits. The deployment loop resistances are measured to ensure they are within their respective normal resistance ranges. The SDM does the following during one portion of the RESISTANCE MEASUREMENT test:

• | Measure the voltage difference between the DRIVER BELT HIGH and the DRIVER BELT LOW.

• | Uses the measured voltage to calculate the resistance of the driver pretensioner deployment loop.

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 driver seat belt pretensioner deployment loop resistance is more than 4.4 ohms. The driver seat belt side buckle pretensioner deployment loop consists of the following components:

• | The driver seat belt side buckle pretensioner.

• | The harness wiring of CKT AM900 (AM950 if vehicle has side air bags).

• | The harness wiring of CKT XM901 (XM950 if vehicle has side air bags).

• | The connector terminal contact.

The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs continuously during each ignition cycle when the IGNITION is within the normal operating voltage range.

### 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. If the resistance in the driver seat belt side buckle pretensioner circuit is less than 4.4 ohms, a Current DTC 35 will change to a History DTC 35, which may be cleared using the scan tool.

### Diagnostic Aids

A poor connection can cause an intermittent condition. Check the following for a poor connection:

• | The 8-way driver seat connector C315A terminals 1 and 2.

• | The SDM terminals 8 and 9.

• | The wire to terminal connections in CKT AM900 (AM950 if vehicle has side air bags).

• | The wire to terminal connections in CKT XM901 (XM950 if vehicle has side air bags).

• | The driver seat belt side buckle pretensioner integral 2-way connector.

Inspect CKTs and AM900 and XM901 (AM950 and XM950 if vehicle has side air bags) carefully for cutting and/or chafing. The diagnostic table directs the technician to note the entry value of the DRIV. PRETENSIONER RES. Comparing the value of the DRIV. PRETENSIONER RES. over multiple ignition cycles can be helpful in determining if an intermittent condition exists.

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 determines whether the malfunction is in CKT AM900 or CKT AM950 between the SDM harness connector and C315.

2. This test determines whether the malfunction is in CKT XM901 or CKT XM950 between the SDM harness connector and C315.

3. This test determines whether the malfunction is in the driver pretensioner belt assembly. This is done by substituting the known good resistance of the load tool and then observing if the malfunction is still present.

4. This test determines if the malfunction is in CKT AM900 in the driver pretensioner seat harness.

5. This test determines if the malfunction is in CKT XM901 in the driver pretensioner seat harness.

#### DTC 35 Driver Pretensioner Deployment Loop Resistance Too High

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. Connect a scan tool to the DLC.
3. Turn the ignition switch to the RUN position.
4. Request the SIR data list display.
5. Read and record on the repair order the driver pretensioner deployment loop resistance LH PRETENS RESIST.

Has LH PRETENS RESIST. been read and recorded on the repair order?

--

Go to Step 3

--

3 |

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 C315 from the 8-way driver seat connector located under the LH front seat track cover.
5. Check for proper connection at terminals 1 and 2 on the 8-way body harness-to-driver seat connector C315.

Are the terminals damaged and/or corroded?

--

Go to Step 3

Go to Step 4

4 | Repair the 8-way body harness-to-driver seat connector C315. Refer to SIR Connector (Plastic Body and Terminal Metal Pin) Repair in this section. Is the repair complete? | -- | Go to Step 4 | --
5 | Check for proper connection at terminals 1 and 2 on C315A on the 8-way driver seat connector. Are the terminals damaged and/or corroded? | -- | Go to Step 5 | Go to Step 6
6 | Repair C315A on the 8-way driver seat connector. Is the repair complete? | -- | Go to Step 22 | --
7 |

1. 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 .
2. Check for proper connection at terminals 8 and 9 on the SDM harness connector.

Are the terminals damaged and/or corroded?

--

Go to Step 7

Go to Step 10

8 | Replace the IP harness Is the replacement complete? | -- | Go to Step 8 | --
9 | Check for proper connection at terminals 8 and 9 on the SDM. Are the terminals damaged and/or corroded? | -- | Go to Step 11 | Go to Step 22
10 | Check for proper connection at terminals 8 and 9 on the SDM. Are the terminals damaged and/or corroded? | -- | Go to Step11 | Go to Step12
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 . Is the replacement complete? | -- | Go to Step 22 | --
12 | Use the J 39200 Digital Multimeter to measure the resistance on the SDM harness connector terminal 8 and the body harness-to-driver seat connector C315 terminal 1. 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 in CKT AM900 or AM950 between the 8-way body harness-to-driver seat connector C315 and the SDM harness connector. Is the repair complete? | -- | Go to Step 22 | --
14 | Measure the resistance between the SDM harness connector terminal 9 to the body harness-to-driver seat connector C315 terminal 2. Is the resistance reading within the specified values? | 0-0.5 ohms | Go to Step 16 | Go to Step 15
15 | Repair the high resistance 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 22 | --
16 |

1. Disconnect the driver seat belt side buckle pretensioner yellow 2-way integral harness connector.
2. Use the J 38715-30 adapter to connect the J 38715-A SIR Driver/Passenger Load Tool to the driver seat belt side buckle pretensioner harness connector.
3. Reconnect the 8-way body harness-to-driver seat connector C315 to the 8-way driver seat connector.
4. Reconnect the SDM harness connector to the SDM.
5. Reconnect the negative battery cable.
6. Turn the ignition switch to the RUN position.
7. Use the scan tool to request the SIR data list display.
8. Read the driver pretensioner loop resistance LH PRETENS RESIST.

Is LH PRETENS RESIST. greater than the specified value?

4.4 ohms

Go to Step 18

Go to Step 17

17 |

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. Replace the driver seat belt side buckle pretensioner assembly. Refer to Seat Belt Buckle Pretensioner Replacement - LH .

Is the replacement complete?

--

Go to Step 22

--

18 |

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 SDM. Refer to Inflatable Restraint Sensing and Diagnostic and Seat Belt Pretensioner Module Replacement .
5. Disconnect the J 38715-A SIR Driver/Passenger Load Tool.
6. Disconnect the 8-way body harness-to-driver seat connect C315.
7. Use the J 39200 Digital Multimeter to measure the resistance between the driver pretensioner yellow 2-way integral harness connector terminal 1 and the driver seat connector C315A terminal 1.

Is the resistance reading within than the specified values?

0-0.5 ohms

Go to Step 20

Go to Step 19

19 | Replace the driver seat belt side buckle pretensioner assembly. Refer to Seat Belt Buckle Pretensioner Replacement - LH . Is the repair complete? | -- | Go to Step 22 | --
20 | Use the J 39200 Digital Multimeter to measure the resistance between the driver pretensioner yellow 2-way integral harness connector terminal 2 and the driver seat connector C315A terminal 2. Is the resistance reading within the specified values? | 0-0.5 ohms | Go to Integrity Check | Go to Step 21
21 | Replace the driver seat belt side buckle pretensioner assembly. Refer to Seat Belt Buckle Pretensioner Replacement - LH . Is the repair complete? | -- | Go to Step 22 | --
22 | Reconnect all the SIR system components. Ensure all the components are properly mounted. Are all the SIR system components reconnected and are all the SIR system components properly mounted? | -- | Go to Step 23 | --
23 | Clear the SIR diagnostic trouble codes. Are the SIR diagnostic trouble codes cleared? | -- | Go to SIR Diagnostic System Check | --