For 1990-2009 cars

### Circuit Description

When the ignition switch is turned ON and during vehicle operation, the SDM performs a test to detect system faults. One test the SDM performs is to monitor the driver side high circuit and driver side low circuit voltage difference. By monitoring voltage, the SDM is able to detect when loop voltage is not between 2.4 and 6.0 volts

### DTC Test Conditions:

DTC B0024 can be set when the driver loop voltage is out of range. The following conditions must be met to set this DTC.

• | Ignition voltage is present at the SDM and continuous.

• | The driver frontal deployment loop voltage is over 6 volts or under 2.4 volts and loop resistance is under 6 ohms

• | Fault needs to only be present for five consecutive sample readings.

### Action Taken:

• | When this fault is detected a current DTC will be set.

• | The air bag light will be turned ON.

• | Driver loop resistance test will be disabled.

### Diagnostic Aids

When attempting to diagnose an intermittent driver loop fault, use the scan tool to monitor current DTCs. Wiggle wires, turn steering wheel and check connections while watching for a current DTC to appear and/or disappear on Scan Tool.

Always start diagnosis of the SIR DTCs with an inspection of wiring and components for visible damage.

A short to ground in circuits 347 or 348 could cause this DTC.

A short between circuits 347 or 348 and another vehicle circuit could cause this DTC.

Always perform the SIR Diagnostic System Check procedure before using this chart.

When measurements are requested in this chart, use SA 91114NE, digital multimeter with correct terminal adapter from SA 9206Z. When a check for proper connection is requested, refer to Intermittent and Poor Connections in Wiring Systems. When a wire connector or terminal repair is requested, use the proper repair parts and refer to Wiring Repairs in Wiring Systems.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

Step | Action | Yes | No
1 | Did you perform the Diagnostic System Check - SIR? | Go to Step 2 | Go to SIR Diagnostic System Check
2 |

1. Turn ON the ignition.
2. Disconnect driver yellow two-way connector located at base of steering column.
3. Check for corroded or damaged harness terminals.

Are the terminals OK?

Go to Step 4

Go to Step 3

3 |

1. Refer to Wiring Repairs in Wiring Systems.
2. Replace terminal(s) with appropriate SIR lead kit.

Are the repairs complete?

Go to Step 16

--

4 |

1. Turn OFF the ignition.
2. Connect SA9409-Z SIR load tool driver harness connector (yellow two-way connector located at the base of the steering column).
3. Turn ON the ignition switch.

Is DTC B0024 current?

Go to Step 5

Go to Step 14

5 |

1. Turn OFF the ignition.
2. Disconnect SA9409-A SIR load tool.
3. Disconnect SDM connector.
4. Measure resistance from circuit 347 to ground.

Does digital multimeter display OL (Infinite)?

Go to Step 7

Go to Step 6

6 |

1. Turn OFF the Ignition.
2. Repair short to ground in circuit 347.

Does digital multimeter display OL (Infinite)?

Go to Step 17

--

7 |

1. Turn OFF the ignition.
2. Measure resistance from circuit 348 to ground.

Does digital multimeter display OL (Infinite)?

Go to Step 9

Go to Step 8

8 |

1. Turn OFF the ignition.
2. Repair short to ground in circuit 348.

Are the repairs complete?

Go to Step 17

--

9 |

1. Turn ON the ignition.
2. With SDM connector and driver inflator disconnected measure voltage between circuit 347 with ground.

Does digital multimeter display less than 1 volt?

Go to Step 11

Step 10

10 |

1. Turn OFF the ignition.
2. Repair short to B+ in circuit 347.

Are the repairs complete?

Go to Step 17

--

11 |

1. Turn ON the ignition.
2. With SDM connector disconnected measure voltage between circuit 348 and ground.

Does the digital multimeter display less than 1 volt?

Go to Step 13

Go to Step 12

12 |

1. Turn OFF the ignition.
2. Repair short to B+ in circuit 348.

Are the repairs complete?

Go to Step 17

--

13 |

1. Turn OFF the ignition.
2. Replace the SDM.

Are the repairs complete?

Go to Step 17

--

14 |

1. Turn OFF the ignition.
2. Remove driver inflator module from steering wheel.
3. Disconnect the coil assembly harness from the inflator module.
4. Reconnect driver inflator module connector at base of steering column.
5. Turn ON the ignition.

Is DTC B0024 current?

Go to Step 16

Step 15

15 |

1. Turn OFF the ignition.
2. Replace the driver inflator module.

Are the repairs complete?

Go to Step 16

--

16 |

1. Turn OFF the ignition.
2. Replace coil assembly.

Are the repairs complete?

Go to Step 17

--

17 |

1. Reconnect all components.
2. Clear all DTCs.

Was the Diagnostic System Check Performed after repair?

--

Go to Step 18

18 | Perform the Diagnostic System Check. | -- | --