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 03: Passenger Occupant Classification Sensor Circuit Voltage Below ThresholdDTC B0074 07: Passenger Occupant Classification Circuit Voltage Above Threshold
DTC B0074 08: Passenger Occupant Classification Circuit Signal Invalid
DTC B0074 0D: Passenger Occupant Classification Sensor Circuit Resistance Above Threshold
DTC B0074 0E: Passenger Occupant Classification Sensor Circuit Resistance Below Threshold
DTC B0074 0F: Passenger Occupant Classification Sensor Circuit Eratic (Wet Seat)
Diagnostic Fault Information
Circuit | Short to Ground | Low Resistance | High Resistance | Open | Short to Voltage | Performance |
|---|---|---|---|---|---|---|
Pressure Sensor Signal | B0074 03 | B0074 0E | B0074 0D | B0074 03 | B0074 07 | B0074 08, B0074 0F |
Pressure Sensor Voltage Reference | B0074 03 | B0074 0E | B0074 0D | B0074 03 | -- | -- |
Pressure Sensor Low Reference | -- | B0074 0E | B0074 0D | B0074 03 | -- | -- |
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 sensor 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 disable the deployment of the instrument panel (I/P) module and then turn the AIR BAG warning 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 pressure sensor signal is less than 0.5 volts or greater than 4.5 volts for 500 milliseconds. |
| • | The PPS detects the voltage at the pressure 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 PPS sensor low reference is 25mA or greater for 500 milliseconds. |
Action Taken When the DTC Sets
| • | The SDM disables the I/P module 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. |
| • | A history DTC will clear once 100 malfunction-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
SIR System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
Important: When removing connectors, inspect for damage or corrosion. Damage or corrosion in the following requires repair or replacement of the affected component/connector:
• PPS pressure sensor • PPS pressure sensor wiring harness connector
- Ignition OFF, disconnect the harness connector at the PPS.
- Test for less then 10 ohms between the ground circuit terminal D and ground.
- Ignition ON, verify a test lamp illuminates between the B+ circuit terminal A and ground.
- Reconnect all PPS components and perform the Passenger Presence System Programming and Setup procedure.
- Clear DTCs, verify DTC B0074 is not set.
| ⇒ | If greater then the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PPS. |
| ⇒ | If the DTC sets, replace the PPS sensor. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for PPS replacement, setup, and programming |
