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

### Circuit Description

When you first turn the ignition switch to the ON position, the inflatable restraint sensing and diagnostic module (SDM) performs tests to diagnose critical malfunctions within itself. Then the SDM performs the following continuous diagnostic tests on the deployment loops:

• | Deployment loop voltage out of range test

• | Deployment loop resistance measurement test

If the voltage out of range test detects a short to voltage condition, the resistance measurement test for that deployment loop will not be performed.

### Conditions for Setting the DTC

• | Deployment loop voltage out of range test.

- | Ignition 1 voltage is within the normal operating voltage range.

- | Passenger frontal high terminal A3 is more than 6 volts for 500 milliseconds.

• | Deployment loop resistance measurement test.

- | Ignition 1 voltage is within the normal operating voltage range.

- | Passenger frontal deployment loop is not shorted to voltage.

- | Passenger frontal high terminal A3 is less than 2 volts AND passenger frontal deployment loop resistance is less than 4.5 ohms for 500 milliseconds.

The passenger frontal deployment loop consists of the following components:

• | Inflatable restraint IP module.

• | Harness wiring of the passenger frontal high circuit.

• | Harness wiring of the passenger frontal low circuit.

• | Connector terminal contact.

### Action Taken When the DTC Sets

• | The SDM sets a DTC B1018.

• | The SDM turns ON the AIR BAG warning indicator.

### Conditions for Clearing the DTC

• | Current DTC

- | Deployment loop voltage out of range test-passenger frontal high terminal A3 is 6 volts or less for 500 milliseconds.

- | Deployment loop resistance measurement test-passenger frontal high terminal A3 is 2 volts or more AND passenger frontal deployment loop resistance is less than 4.5 ohms for 500 milliseconds.

• | History DTC

- | Issue a scan tool CLEAR CODES command.

- | Once 250 malfunction free ignition cycles have occurred.

### Diagnostic Aids

A short to B+ or short to ground in the inflatable restraint IP module circuit can cause an intermittent condition. Inspect the passenger frontal high circuit and the passenger frontal low circuit carefully for cutting or chafing. Wiring pigtail damage requires replacement of the inflatable restraint IP module.

### Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

1. This step checks the inflatable restraint steering wheel module yellow 2-way connector..

2. This step checks to see if there is a malfunctioning inflatable restraint IP module.

3. This step checks to see if there is a short to ground in the passenger frontal high circuit.

4. This step checks to see if there is a short to ground in the passenger frontal low circuit.

5. This step checks to see if there is a short to B+ in the passenger frontal high circuit.

6. This step determines if there is a short to B+ in the passenger frontal low circuit or if there is a malfunctioning SDM.

7. This step clears all SIR DTCs.

#### DTC B1018 Passenger Frontal Deployment Loop Voltage Out Of Range

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 inflatable restraint IP module yellow 2-way connector.
3. Check the wiring harness side of the inflatable restraint IP module yellow 2-way connector for corrosion or damaged terminals.

Are the inflatable restraint IP module yellow 2-way connector and terminals free from damage and corrosion?

--

Go to Step 4

Go to Step 3

3 | Repair or replace the wiring harness side of the inflatable restraint IP module yellow 2-way connector components. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
4 |

1. Reconnect the inflatable restraint IP module yellow 2-way connector.
2. Make sure that the connector position assurance (CPA) is properly installed.
3. Turn the ignition switch to the ON position.
4. Use the scan tool to request the SIR DTC display.

Is DTC B1018 current?

--

Go to Step 5

Go to Diagnostics Aids

5 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the inflatable restraint IP module yellow 2-way connector and the inflatable restraint steering wheel module yellow 2-way connector.
3. Install the J 38715-A SIR Driver/Passenger Load Tool to the wiring harness side of the inflatable restraint IP module yellow 2-way connector and the inflatable restraint steering wheel module yellow 2-way connector. Use the J 38715-25 adaptor for the inflatable restraint steering wheel module yellow 2-way connector and the J 38715-15 adaptor for the inflatable restraint IP module yellow 2-way connector.
4. Turn the ignition switch to the ON position.
5. Use the scan tool to request the SIR DTC display.

Is DTC B1018 current?

--

Go to Step 7

Go to Step 6

6 |

1. Turn the ignition switch to the OFF position.
2. Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement .

Is the repair complete?

--

Go to Step 16

--

7 |

1. Turn the ignition switch to the OFF position.
2. Remove the J 38715-A .
3. Disconnect the inflatable restraint sensing and diagnostic module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
4. Use the J 39200 Digital Multimeter (DMM) to measure the resistance between terminal A3 of the SDM wiring harness connector and a known good ground.

Is the measured resistance less than the specified value?

OL

Go to Step 8

Go to Step 9

8 | Locate and repair a short to ground in the passenger frontal high circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
9 | Use the J 39200 to measure the resistance between terminal A8 of the SDM wiring harness connector and a known good ground. Is the measured resistance less than the specified value? | OL | Go to Step 10 | Go to Step 11
10 | Locate and repair a short to ground in the passenger frontal low circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
11 |

1. Turn the ignition switch to the ON position.
2. Use the J 39200 to measure the voltage between terminal A3 of the SDM wiring harness connector and a known good ground.

Is the measured voltage less than the specified value?

1 V

Go to Step 13

Go to Step 12

12 | Locate and repair a short to B+ in the passenger frontal high circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
13 | Use the J 39200 to measure the voltage between terminal A8 of the SDM wiring harness connector and a known good ground. Is the measured voltage less than the specified value? | 1 V | Go to Step 15 | Go to Step 14
14 | Locate and repair a short to B+ in the passenger frontal low circuit. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 16 | --
15 |

1. Turn the ignition switch to the OFF position.
2. Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Is the repair complete?

--

Go to Step 16

--

16 |

1. Reconnect all SIR components.
2. Make sure that all components and connectors are properly mounted.
3. Turn the ignition switch to the ON position.
4. Use the scan tool to clear all current and history SIR DTCs.

Have all current and history DTCs been cleared?

--

Go to SIR Diagnostic System Check

--