Chevrolet Trax: DTC B0074: Passenger presence sensor

Diagnostic Instructions

• 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.

DTC Descriptors

DTC B0074 00

Passenger Presence Sensor Circuit Malfunction

DTC B0074 04

Passenger Presence Sensor Open

Circuit/System Description

The passenger presence module monitors the passenger presence sensor status continuously. Whenever the passenger presence sensor has an internal malfunction, the passenger presence module will set DTC B0074.

Conditions for Running the DTC

Ignition voltage is between 9-16 V.

Conditions for Setting the DTC

B0074 00

The passenger presence module has detected a disconnection from the passenger presence sensor.

B0074 04

The passenger presence module has detected an open circuit.

Action Taken When the DTC Sets

The Inflatable Restraint Sensing and Diagnostic Module will set a DTC B0081 00 after receiving a fault present message from the passenger presence module and requests the instrument cluster to illuminate the AIR BAG indicator.

Conditions for Clearing the DTC

• The condition for setting the DTC no longer exists.
• A history DTC will clear once 100 malfunction-free ignition cycles have occurred.

Diagnostic Aids

• If either the Inflatable Restraint Sensing and Diagnostic Module or Passenger Presence System 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, Power Inverter, 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 (Encore), SIR Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Supplemental Inflatable Restraint System Description and Operation

Electrical Information Reference

• Circuit Testing
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE:

This system allows you to service each component separately (module and sensor/sensing mat). Perform a Passenger Presence System Rezeroing

• Passenger presence sensor
• Passenger presence sensor harness connector
• Passenger presence module
• Passenger presence module harness connector
• Seat wiring harness to vehicle harness connector

The connector and connector position assurance (CPA) may seat independent of each other. Both the connector and CPA should seat with an audible and/or tactile click.

1. Observe with the scan tool if the fault changes status while moving the passenger seat forward and backward through its full range of motion. The status should stay consistent.

The status changes

If the status changes this could be indication of a seat to vehicle harness connection issue, refer to Circuit/System Testing.

The status does not change

2. Observe with the scan tool if the fault changes status while moving the harness near each connector listed below. The status should stay consistent.

• Passenger presence module
• Passenger presence sensor
• Any seat harness inline
• The status changes

If the reading is erratic while moving the harness, perform the following:

• Inspect each connector terminal for damage or corrosion and repair as necessary.
• Insure each connector and CPA is correctly seated.
• The status does not change

3. All OK.

Circuit/System Testing

NOTE:

This system allows you to service each component separately (module and sensor/sensing mat). Perform a Passenger Presence System Rezeroing

1. Verify that all K85 Passenger Presence Module and B60 Passenger Presence Sensor connectors are fully seated.
2. Verify DTC B0074 is not set.

• DTC B0074 is set.
• Replace the B60 Passenger Presence Sensor.
• DTC B0074 does not set.

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

Control Module References for Passenger Presence Sensor, Passenger Presence Module, or Inflatable Restraint Sensing and Diagnostic Module replacement, programming, and setup

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