B0074
DTC B0074
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.
DTC Descriptors
DTC B0074 00
- Passenger Presence Sensor
DTC B0074 0D
- Passenger Presence Sensor Circuit Resistance Above Threshold
DTC B0074 0E
- Passenger Presence Sensor Circuit Resistance Below Threshold
DTC B0074 0F
- Passenger Presence Sensor Circuit Erratic (Wet Seat)
Diagnostic Fault Information
Circuit/System Description
The passenger presence sensor continually monitors itself and if a fault in this circuit occurs, a DTC will set. When the inflatable restraint sensing and diagnostic module (SDM) detects this DTC within the passenger presence system (PPS), it will notify the customer of the enable/disable status by illuminating the OFF indicator on the PASSENGER AIR BAG ON/OFF indicators. Then the PPS will communicate to the SDM through serial data communications that a PPS fault is present. The SDM will then disable the deployment of the passenger instrument panel air bag and then illuminate the AIR BAG warning indicator.
Conditions for Running the DTC
Ignition voltage is between 9-16 volts.
Conditions for Setting the DTC
* The PPS detects the voltage at the passenger presence sensor signal is less than 0.5 volts or greater than 4.5 volts for 500 milliseconds.
* The PPS detects the voltage at the passenger presence sensor voltage reference is less than 4.5 volts or greater than 9.1 volts for 500 milliseconds.
* The PPS detects the amperage at the passenger presence sensor low reference is 25 mA or greater for 500 milliseconds.
Action Taken When the DTC Sets
* The SDM disables the passenger instrument panel air bag deployment loop.
* The SDM will illuminate the OFF portion of the PASSENGER AIR BAG ON/OFF indicator.
* The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.
Conditions for Clearing the DTC
The condition for setting the DTC no longer exists.
Diagnostic Aids
* If either the SDM or PPS were replaced verify that the correct part numbers were used for the vehicle application.
* If this DTC is set as either current or history it may have been caused by an electronic device. If an electronic device (Computers, MP3 Players, Cell Phones, Diagnostic Scan Tool, etc.) was placed on the passenger seat the passenger presence module may command the passenger air bag indicator to turn on and/or command the passenger seat belt indicator to turn on. Make sure there are no objects on the passenger seat and clear the DTCs. If this DTC resets then perform this diagnostic. If the DTC does not reset there is no further work needed on the passenger presence system.
* If this DTC is set as either current or history it may have been caused by an aftermarket seat heater. The aftermarket seat heater may command the passenger air bag indicator to turn on and/or command the passenger seat belt indicator to turn on. Remove the aftermarket seat heater from the passenger seat and clear the DTCs. If this DTC resets then perform this diagnostic. If the DTC does not reset there is no further work needed on the passenger presence system.
Reference Information
Schematic Reference
SIR Schematics (without WHB) (SIR Schematics (without WHB))SIR Schematics (WHB) (SIR Schematics (WHB))
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)
* SIR/SRS Wiring Repairs (SIR/SRS Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Testing
Note: When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector:
* Passenger presence sensor
* Passenger presence sensor wiring harness connector
1. Verify that DTC B0074 0F is not set.
• If the DTC is set, verify the seat is dry. If the seat is wet, allow 24-48 hours dry time.
2. Ignition OFF, disconnect the harness connector at the passenger presence sensor.
3. Test for less then 10 ohms between the ground circuit terminal 3 and ground.
• If greater then the specified range, test the ground circuit for an open/high resistance.
4. Ignition ON, verify a test lamp illuminates between the ignition circuit terminal 1 and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
5. Ignition OFF, disconnect the harness connector at the SDM.
6. Test for infinite resistance between the serial data circuit terminal 2 and ground.
• If less than the specified value, test the serial data circuit for a short to ground.
7. Ignition ON, test for less than 1 volt between the serial data circuit terminal 2 and ground.
• If greater than the specified range, test the serial data circuit for a short to voltage.
8. Test for less than 1 ohm on the serial data circuit between the passenger presence sensor terminal 2 and the SDM terminal 2.
• If greater than the specified range, test the signal circuit for open/high resistance.
9. Reconnect all PPS components and perform the Passenger Presence System Preload Test (Passenger Presence System Preload Test) procedure.
10. Clear DTCs, verify DTC B0074 is not set.
• If the DTC sets, replace the passenger presence sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning) for passenger presence system replacement, setup, and programming