Circuit Description
The inflatable restraint passenger presence system (PPS) is used to monitor the weight of an occupant on the front outboard passenger seat and communicate the status to the sensing and diagnostic module (SDM) whether to enable or suppress the deployment of the I/P module. The PPS consist of an electronic control module, silicone filled sensor pad, pressure sensor, seat belt tension retractor sensor, wiring harness, and PASSENGER AIR BAG ON/OFF indicators. The silicone filled sensor pad is located under the passenger seat foam cushion and is connected by a hose clamped to the 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 sends a voltage signal to the PPS module. If the pressure from the occupant's weight is less than a specified value, the PPS module will send a suppress signal to the SDM to disable the I/P module. If the pressure from the occupant's weight is higher than a specified value, the PPS module will send an enable signal to the SDM to enable the I/P module. The PPS module will notify the customer of the enable/disable status by turning on one of the PASSENGER AIR BAG ON/OFF indicators located on the rear view mirror. The PPS monitors itself for faults and will set flash diagnostic trouble codes (DTCs) if a fault is detected. The PPS will also notify the SDM of a fault. The SDM will respond by setting DTC B0092 and requesting the instrument panel cluster (IPC) to turn the AIR BAG indicator ON.
Conditions for Running the DTC
Ignition 1 voltage is within the normal operating voltage range.
Conditions for Setting the DTC
| • | The PPS detects the voltage at PPS sensor signal is less than 0.05 volts or greater than 4.5 volts for 500 milliseconds. |
| • | The PPS detects the voltage at PPS sensor 5-volt reference is less than 4.5 volts or greater than 9.1 volts for 500 milliseconds. |
| • | The PPS detects the amperage at PPS sensor low reference is 25 ma or greater for 500 milliseconds. |
Action Taken When the DTC Sets
| • | The SDM disables the I/P module deployment loop. |
| • | The SDM commands the AIR BAG indicator ON via Class 2 serial data. |
Conditions for Clearing the DTC
| • | The condition responsible for setting the DTC no longer exists. |
| • | You issue a scan tool CLEAR DTCs command. |
| • | A history DTC will clear once 255 malfunction free ignition cycles have occurred. |
Diagnostic Aids
The following can cause an intermittent condition:
| • | A short between the PPS sensor signal, 5-volt reference, and low reference circuits |
| • | An open or high resistance between the PPS sensor signal, 5-volt reference, and low reference circuits |
| • | Inspect the PPS sensor signal, 5-volt reference, and low reference circuits carefully for cutting and/or chafing |
Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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Inspects the PPS pressure sensor connector.
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Tests for a short to ground, a high resistance, or an open in the PPS sensor signal circuit.
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Tests for a short to ground, a high resistance, or an open in the PPS sensor 5-volt reference circuit.
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Tests for a short to ground, a high resistance, or an open in the PPS sensor low reference circuit.
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Tests for a short to voltage in the PPS sensor signal circuit.
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Tests the PPS sensor signal circuit input voltage range.
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Tests for a short to voltage in the PPS sensor 5 volt reference circuit.
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Tests for a short to voltage in the PPS sensor low reference circuit.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | ||||
1 | Did you perform the Diagnostic System Check - SIR? | -- | Go to Step 2 | |
Does the PPS pressure sensor terminals or harness connector exhibit any signs of damage or corrosion? | -- | Go to Step 3 | Go to Step 4 | |
3 |
Did you complete the replacement? | -- | Go to Step 13 | -- |
4 |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 5 |
Test the PPS sensor signal circuit for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 6 | |
Test the PPS sensor 5-volt reference circuit for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 7 | |
Test the PPS sensor low reference circuit for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 8 | |
Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 | |
Test the PPS sensor signal circuit input voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Does the voltage measure within the specified range ? | 0.05-4.5 V | Go to Step 10 | Go to Step 12 | |
Test the PPS sensor 5-volt reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11 | |
Test the PPS sensor low reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12 | |
12 |
Important: The PPS is a calibrated system. The PPS must be rezeroed after replacement. Replace the PPS. Refer to Inflatable Restraint Passenger Presence System Replacement - Front . Did you complete the replacement? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
