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.
At this time, the SDM will establish communication with the passenger presence detection (PPD)/seat belt reminder (SBR) and the PPD/SBR will respond to the SDM by commanding the passenger air bag OFF indicator On for five seconds.
The SDM monitors the PPD/SBR status (occupied, not occupied, seated, defect) cyclically. These 4 messages should transmit every 1.2 seconds to the SDM.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B1406 PPD/SBR Malfunction
Conditions for Running the DTC
Ignition voltage is within the normal operating voltage range.
Conditions for Setting the DTC
The PPD sensor is inoperative.
Action Taken When the DTC Sets
The SDM commands the air bag indicator ON.
Conditions for Clearing the DTC
Caution: The sensing and the diagnosis module (SDM) can maintain sufficient voltage to deploy the airbags and pretensioners for up to 1 minute after the ignition has been turned OFF and the fuse has been removed. If the airbags and pretensioners are not disconnected, do not begin service until one minute has been passed after disconnecting power to the SDM. Failure to do so may cause personal injury.
Caution: Do not strike or jolt the inflatable restraint sensing and diagnostic module (SDM). Before applying power to the SDM, make sure that it is securely fastened with the arrow facing toward the front of the vehicle. Failure to observe the correct installation procedure could cause SIR deployment, personal injury, or unnecessary SIR system repairs.
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 Handling Caution in the Preface section. Caution: Refer to Sensing and Diagnostic Module Voltage after Ignition is Turned Off 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 | Inspect the fuse F11. Is fuse F11 blown? | -- | Go to Step 3 | Go to Step 4 |
3 | Replace the fuse F11. Did you complete the replacement? | -- | Go to Step 9 | -- |
4 |
Is the voltage as specified? | 9-16 V | Go to Step 5 | Go to Step 7 |
5 |
Is the resistance as specified? | 0 ohms | Go to Step 6 | Go to Step 7 |
6 | Measure the resistance between terminal 2 of the PPD sensor connector and terminal 63 of the SDM connector. Is the resistance as specified? | 0 ohms | Go to Step 8 | Go to Step 7 |
7 | Replace the air bag wiring. Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the PPD sensor. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK | |
