For 1990-2009 cars
SIR Components
SIR Schematics
Handling ESD Sensitive Parts Notice
SIR Caution
SIR Caution
Handling ESD Sensitive Parts Notice

### Circuit Description

When you first turn the ignition switch to the RUN position, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Next the SDM measures IGNITION and the deployment loop voltages to make sure they are within their respective normal voltage ranges. Then the SDM proceeds with the RESISTANCE MEASUREMENT test. During one portion of the RESISTANCE MEASUREMENT test, the SDM does the following:

• | Grounds the Passenger Belt Low terminal 15 through an internal current sink.

• | Connects the Passenger Belt High terminal 45 to an internal constant current source. This current produces proportional voltage drops in the deployment loop.

• | Measures the voltage difference between Passenger Belt High and Passenger Belt Low.

• | Calculates the resistance of the passenger seat belt pretensioner deployment loop using the measured voltage.

### Conditions for Setting the DTC

• | The driver and passenger seat belt pretensioner deployment loops are not open.

• | The driver and passenger seat belt pretensioner deployment loops are not shorted to voltage.

• | The passenger seat belt pretensioner deployment loop is not shorted to ground.

• | The passenger seat belt side buckle deployment loop resistance is less than 1.35 ohms. The passenger seat belt pretensioner deployment loop consists of the following components:

- | Passenger seat buckle side belt.

- | Harness wiring of CKT 2116.

- | Harness wiring of CKT 2117.

- | Connector terminal contact.

The RESISTANCE MEASUREMENT test checks for this malfunction. This test only occurs once each ignition cycle when 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 DTC

| The resistance of the passenger seat belt pretensioner deployment loop is more than 1.85 ohms and the ignition switch is cycled.

• | History DTC

- | You issue a scan tool CLEAR CODES command.

- | Once 250 malfunction free ignition cycles have occurred.

When you issue a scan tool CLEAR CODES command and the malfunction is still present, the DTC will not reappear until the next ignition cycle.

### Diagnostic Aids

The following can cause an intermittent condition:

• | A short circuit between CKT 2116 and CKT 2117.

• | A malfunctioning shorting bar on the passenger seat buckle side belt yellow 2-way yellow connector.

The diagnostic table directs the technician to note the entry value of RH PRETENS. RESIST. Comparing the value of RH PRETENS. RESIST. 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 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 the deployment loop resistance measured by the inflatable restraint sensing and diagnostic module (SDM).

2. This test checks for proper contact or corrosion of the yellow 2-way connector.

3. This test isolates the malfunction to one side of the passenger seat buckle side belt yellow 2-way connector.

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

5. This test checks for a short between CKT 2116 and CKT 2117.

#### DTC B1031 RH Pretens. Deploy. Loop Resistance Low

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 passenger seat belt pretensioner deployment loop resistance RH PRETENS. RESIST.

Has RH 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. Disconnect the inflatable restraint front side impact module (RH) and passenger seat buckle side belt yellow 2-way connectors located under the front passenger seat.
3. Check for proper connection at terminals A and B on the body harness side of the yellow 2-way connector.

Are the terminals damaged or corroded?

--

Go to Step 4

Go to Step 6

4 | Replace the passenger seat buckle side belt yellow 2-way body harness connector. Refer to Wiring Repair in this section. Are the repairs complete? | -- | Go to Step 5 | --
5 | Check for proper connection at terminals A and B on the passenger seat buckle side belt yellow 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 7 | Go to Step 19
6 | Check for proper connection at terminals A and B on the passenger seat buckle side belt yellow 2-way connector. Are the terminals damaged or corroded? | -- | Go to Step 7 | Go to Step 8
7 | Replace the passenger seat buckle side belt. Refer to Seat Buckle Side Belt Replacement . Has the passenger seat buckle side belt been replaced? | -- | Go to Step 19 | --
8 |

1. Reconnect the inflatable restraint front side impact module (RH) and passenger seat buckle side belt yellow 2-way connectors located under the front passenger seat.
2. Turn the ignition switch to the RUN position.
3. Using the scan tool, request the SIR data list display.
4. Read the passenger seat belt pretensioner deployment loop resistance RH PRETENS. RESIST.

Is RH PRETENS. RESIST. less than the specified value?

1.5 ohms

Go to Step 10

Go to Step 9

9 |

1. Turn the ignition switch to the OFF position.
2. Replace the passenger seat buckle side belt yellow 2-way body harness connector. Refer to Wiring Repair in this section.

Are the repairs complete?

--

Go to Step 19

--

10 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint front side impact module (RH) and passenger seat buckle side belt yellow 2-way connectors located under the passenger seat.
3. Connect the J 38715-A SIR Driver/Passenger Load Tool STEERING COLUMN and PASSENGER INFLATOR connectors to the yellow 2-way harness connectors.
4. Turn the ignition switch to the RUN position.
5. Using the scan tool, request the data list display.
6. Read the passenger seat belt pretensioner deployment loop resistance RH PRETENS. RESIST.

Is RH PRETENS. RESIST. less than the specified value?

1.5 ohms

Go to Step 12

Go to Step 11

11 |

1. Turn the ignition switch to the OFF position.
2. Replace the passenger seat buckle side belt. Refer to Seat Buckle Side Belt Replacement .

Has the passenger seat buckle side belt been replaced?

--

Go to Step 19

--

12 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
3. Disconnect the J 38715-A .
4. Check for proper connection at terminals 15 and 45 on the SDM harness connector.

Is the harness connector damaged or corroded?

--

Go to Step 13

Go to Step 15

13 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM) harness connector. Refer to Wiring Repair in this section. Are the repairs complete? | -- | Go to Step 14 | --
14 | Check for proper connection at terminals 15 and 45 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 16 | Go to Step 19
15 | Check for proper connection at terminals 15 and 45 on the SDM. Are the terminals damaged or corroded? | -- | Go to Step 16 | Go to Step 17
16 | Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement . Are the repairs complete? | -- | Go to Step 19 | --
17 |

1. Zero the J 39200 Digital Multimeter.
2. Measure the resistance from the passenger seat buckle side belt yellow 2-way body harness connector terminal A to terminal B.

Is the resistance reading within the specified values?

0-0.5 ohms

Go to Step 18

Go to Integrity Check

18 | Repair the short between CKT 2116 and CKT 2117. Are the repairs complete? | -- | Go to Step 19 | --
19 | 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 20 | --
20 | Clear all the SIR DTCs. Have all the DTCs been cleared? | -- | Go to SIR Diagnostic System Check | --