Circuit Description
When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) will perform a turn-on test to diagnose critical malfunctions within the SDM itself.
Upon passing these tests, the ignition and deployment loop voltages are measured to ensure that these voltages are within the normal ranges. The SDM monitors the voltages at the driver low and the passenger low to detect shorts to ground or voltage in the deployment loops.
The SDM tests the wiring connection to extra devices, such as the side impact sensor, by letting an infinitesimal current flow through the internal circuit to verify the resistance. If the voltage is out of range, the SDM is unable to test the air bag system properly.
In the case of DTC B1103, test the battery and if necessary replace the battery with a new one. Erase the DTC using the scan tool.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1329 Front End Sensor 1 Invalid Serial Data Received
Conditions for Running the DTC
Ignition voltage is within the normal operating voltage range.
Conditions for Setting the DTC
The early crash sensor - driver (LH) is defective or the air bag wiring harness is damaged.
Action Taken When the DTC Sets
The SDM commands the AIR BAG indicator ON.
Conditions for Clearing the DTC
The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
|
Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off Caution in the Preface section. Caution: Refer to Sensing and Diagnostic Module Handling Caution in the Preface section. Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | ||||
1 | Did you perform a Diagnostic System Check - Vehicle? | -- | Go to Step 2 | |
2 |
Is the SDM charger discharged? | -- | Go to Step 3 | -- |
3 | Visually inspect for damage to the early crash sensor - driver (LH) wiring. Is the early crash sensor - driver (LH) wiring damaged? | -- | Go to Step 4 | Go to Step 5 |
4 | Replace the air bag wiring. Did you complete the replacement? | -- | Go to Step 8 | -- |
5 |
Are the resistances approximately equal to the indicated value? | 0 ohms | Go to Step 6 | Go to Step 4 |
6 | Test the resistance between the terminal 74 and 75 of the SDM connector. Is the resistance equal to the indicated value? | ∞ | Go to Step 7 | Go to Step 4 |
7 | Replace the early crash sensor - driver (LH). Did you complete the replacement? | -- | Go to Step 8 | -- |
8 |
Does the DTC reset? | -- | Go to Step 9 | System OK |
9 | Verify the part number of the early crash sensor - driver (LH). Is the part number correct for the vehicle? | -- | Go to Step 2 | Go to Step 7 |
