Diagnostic Instructions
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. |
Reference Information
Electrical Information Reference
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:
| • | The PPS pressure sensor |
| • | The PPS pressure sensor wiring harness connector |
| • | The PPS module wiring harness connector |
- Ignition OFF, Disconnect the PPS module harness connector.
- 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. |
- 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. |
- Reconnect all PPS components and perform the
Passenger Presence System Preload Test
.
- 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.
