• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Low Reference | -- | 2 | -- | -- |
Seat Belt Switch Signal | 1 | 2 | -- | -- |
Ignition 1 Voltage | 3 | 3 | -- | -- |
Passenger Seat Belt Indicator Control | 4 | 5 | -- | -- |
|
The seat belt buckle switch is a 2-wire switch wired to the inflatable restraint sensing and diagnostic module (SDM) using a signal circuit and a low reference circuit. When the seat belt is unbuckled the switch is closed, and when the seat belt is buckled the switch is open. When the passenger presence system (PPS) indicates that the seat is occupied, the SDM sends the status of the passenger seat belt via serial data to the instrument panel cluster (IPC). After receiving the message, the IPC controls the illumination of the passenger seat belt indicator by grounding the indicator control circuit. If an occupant is seated in the front passenger seat and the seat belt is unfastened, the SDM will send a message to the IPC to illuminate the fasten seat belt indicator for approximately 72 seconds or until the seat belt is fastened.
Seat Belt System Description and Operation
Control Module References for Scan Tool Information
⇒ | If the indicator is always ON or always OFF, refer to Indicator Circuit Test. |
⇒ | If the parameter displays incorrectly, refer to Switch Circuit Test. |
⇒ | If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the inflatable restraint passenger air bag ON/OFF indicator. |
Important: Allow 5 seconds after seat is occupied for test lamp to change states.
⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the IPC. |
⇒ | If the test lamp is always OFF, test the control circuit for an open/high resistance. If the circuit tests normal, replace the IPC. |
Important: When removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector.
• The seat belt switch • The seat belt switch harness connector • The SDM • The SDM harness connector
⇒ | If not as specified, replace the seat belt buckle. |
⇒ | If the parameter is Unbuckled, test the seat belt switch signal circuit for a short to ground. If the circuit tests normal replace the SDM. |
⇒ | If the parameter is Buckled, test the signal and the low reference circuits for open/high resistance. If the circuits test normal, replace the SDM. |
⇒ | If not the specified range, replace the seat belt switch. |
⇒ | If greater than the specified range, replace the seat belt switch. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for SDM or IPC replacement, setup, and programming |