B0074

DTC B0074

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 01
- Passenger Occupant Classification Sensor Circuit Short to Battery

DTC B0074 02
- Passenger Occupant Classification Sensor Circuit Short to Ground

DTC B0074 08
- Passenger Occupant Classification Sensor Circuit Signal Invalid

DTC B0074 11
- Passenger Occupant Classification Sensor Circuit Above Maximum Threshold

Circuit/System Description

The passenger presence system (PPS) uses a silicone filled sensor pad located underneath the passenger seat foam cushion and is connected by a hose clamp to a pressure sensor. The weight of the occupant sitting in the front passenger seat is measured as a pressure change within the bladder by the pressure sensor. The pressure sensor is a 3-wire sensor consisting of a power, ground, and signal circuit. The PPS continually monitors itself and if a fault in this circuit occurs, a DTC will set. When the sensing and diagnostic module (SDM) detects this DTC within the PPS, it will notify the customer of the enable/disable status by turning ON 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 suppress the deployment of the instrument panel (I/P) module and then turn the AIR BAG indicator ON.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC

* The PPS detects the voltage at the PPS sensor is less than 0.05 volt or greater than 4.5 volts for 500 milliseconds.
* The PPS detects the amperage at the PPS sensor low reference is 25 mA or greater for 500 milliseconds.

Action Taken When the DTC Sets

* The PPS will set a DTC, and then communicate with the SDM via serial data communications.
* The SDM disables the I/P module deployment loop.
* The PPS will turn ON the passenger air bag status OFF indicator.
* The SDM commands ON the AIR BAG warning lamp via serial data communications.

Conditions for Clearing the DTC

* The condition responsible for setting the DTC no longer exists and the scan tool Clear DTCs function is used.
* A history DTC will clear once 255 malfunction-free ignition cycles have occurred.

Circuit/System Testing

1. 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 PPS pressure sensor

* The PPS module

* The PPS pressure sensor wiring harness connector

* The PPS module wiring harness connector

Ignition OFF, Disconnect the PPS module harness connector.
2. Ignition OFF, test for less then 1 ohm of resistance between the PPS sensor ground circuit and ground.

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

3. Ignition ON, verify a test lamp illuminates between the PPS B + circuit terminal A and ground.

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

4. Reconnect all PPS components and perform the Passenger Presence System Preload Test.
5. Verify DTC B0074 does not exist.

• If DTC B0074 is set, replace the PPS.

Repair Instructions

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

Control Module References for PPS replacement, setup, and programming