Air Bag Indicator Circuit Malfunction (Passenger)

Air Bag Indicator Circuit Malfunction (Passenger)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information





Circuit/System Description (C99)

When the ignition switch is turned to ON, the sensing and diagnostic module (SDM) continuously checks the air bag enable/disable switch position switch and circuit defect by letting regular voltage flow through the switch circuit and verifying the current. The passenger air bag switch controls when the air bag is enabled or disabled and notifies the driver when the passenger instrument panel air bag is enabled or disabled using the passenger air bag ON/OFF indicators. When the sensing and diagnostic module (SDM) receives the signal from the passenger air bag disable switch (on/off), the SDM will then provide voltage to the appropriate indicator.

Circuit/System Description (ALO)

The passenger air bag ON/OFF indicators are used to notify the driver when the passenger presence system has enabled or disabled the passenger instrument panel air bag. When the ignition is turned ON, the ignition voltage is supplied to the passenger presence module. When the sensing and diagnostic module (SDM) receives the appropriate serial data message from the passenger presence system the SDM will then provide voltage to the appropriate indicator.

Reference Information
Schematic Reference

SIR Schematics ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

SIR System Description and Operation (SIR System)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Note: The passenger air bag ON and OFF indicators may not operate as expected if there are supplemental inflatable restraint (SIR) DTCs. Repair all SIR DTCs before proceeding with this diagnostic.

1. (C99) Observe the scan tool Passenger Air Bag Disabled Switch parameter while commanding the passenger air bag ON and OFF by using the S40 passenger air bag disable switch. The value should change between On and Off. If the value does not change refer to Passenger Air Bag Disable Switch Circuit/System Testing.
2. (ALO) Ignition ON, with the passenger seat unoccupied, verify the scan tool Passenger Seat Occupancy Status parameter is Empty. If it is not the Passenger Presence System Module has set a DTC. Diagnose the DTC.
3. With the passenger seat unoccupied, verify the passenger air bag OFF indicator is illuminated. If it is not refer to Passenger Air Bag Indicator Circuit/System Testing.
4. (ALO) With the passenger seat occupied, verify the scan tool Passenger Seat Occupancy Status parameter is Occupied. If it is not the Passenger Presence System Module has set a DTC. Diagnose the DTC.
5. With the passenger seat occupied, verify the passenger air bag ON indicator is illuminated. If it is not refer to Passenger Air Bag Indicator Circuit/System Testing.

Passenger Air Bag Disable Switch Circuit/System Testing (C99)

1. Ignition OFF, disconnect the harness connector at the S40 passenger air bag disable switch.
2. Test for less than 30 ohm between the ground circuit terminal 3 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance. If the circuit tests normal, replace the K36 SDM.

3. Ignition ON, test for 4.75-5.25V between the signal circuit terminal 1 and ground.

• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K36 SDM.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K36 SDM.

4. If all circuits test normal, replace the S40 passenger air bag disable switch.

Passenger Air Bag Indicator Circuit/System Testing

Note: removing connectors inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected.

* P14 Passenger Air Bag Indicator.
* P14 Passenger Air Bag Indicator wiring harness.

1. Ignition OFF, disconnect the harness connector at the P14 Passenger Air Bag Indicator.
2. Test for less than 5 ohm between the ground circuit terminal 2 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, with the passenger seat occupied, verify that a test lamp does not illuminate between the control circuit terminal 3 and ground.

• If the test lamp is illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the K36 SDM

4. With the passenger seat unoccupied, verify that a test lamp illuminates between the control circuit terminal 3 and ground.

• If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the K36 SDM.

5. With the passenger seat unoccupied verify that a test lamp does not illuminate between the control circuit terminal 1 and ground.

• If the test lamp is illuminated, test the control circuit for a short to voltage. If the circuit tests normal, replace the K36 SDM.

6. With the passenger seat occupied verify that a test lamp illuminates between the control circuit terminal 1 and ground.

• If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal replace the K36 SDM.

7. If all circuits test normal, replace the P14 Passenger Air Bag Indicator. Refer to Inflatable Restraint Instrument Panel Module Indicator Replacement (Service and Repair).

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for Passenger Air Bag Disable Switch and SDM replacement, setup, and programming