GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2009 🢒 HHR 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC 301A

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 Descriptor

DTC 301A: Passenger Occupant Classification Sensor Circuit

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

5-Volt Reference

3003-3059, 300A, 301A, 303A-303E, 305A-305C

3003-3059, 300A, 301A, 303A-303E, 305A-305C

3003-3059, 300A, 301A, 303A-303E, 305A-305C

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PPS Sensor Signal

3003-3059, 300A, 301A, 303A-303E, 305A-305C

3003-3059, 300A, 301A, 303A-303E, 305A-305C

3003-3059, 300A, 301A, 303A-303E, 305A-305C

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Low Reference

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3003-3059, 300A, 301A, 303A-303E, 305A-305C

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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, DTC 301A will set. When the PPS detects this DTC within the PPS, it will notify the customer of the enable/disable status by illuminating the OFF indicator on the PASSENGER AIR BAG ON/OFF indicators.

Then the PPS will communicate to the sensing and diagnostic module (SDM) through a serial data communications circuit that a PPS fault is present. The SDM will then set DTC B0081 indicating a problem within the PPS and will suppress the deployment of the instrument panel (I/P) module and then illuminate the AIR BAG warning indicator.

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 signal is less than 0.5 volt or greater than 4.5 volts for 500 milliseconds.
    • The PPS detects the voltage at the 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 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.
    • The SDM will set DTC B0081.
    • The SDM will disable the I/P module deployment loop.
    • The PPS will illuminate the passenger air bag status OFF indicator.
    • The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG warning 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

SIR Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

SIR System Description and Operation

Electrical Information Reference

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

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 module
       • PPS wiring harness connector

  1. Ignition OFF, disconnect the harness connector at the inflatable restraint front PPS sensor.
  2. Ignition OFF, test for less than 1.0 ohm between the low reference circuit terminal C and ground.
    3. ⇒If not within the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the PPS.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal A and ground.
    4. ⇒If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the PPS module.
    ⇒If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PPS module.
  4. Ignition OFF, disconnect the harness connector at the PPS module.
  5. Ignition OFF, test for infinite resistance between the signal circuit terminal B and ground.
    6. ⇒If not the specified value, test the signal circuit for a short to ground.
  6. Ignition ON, test for less than 1.0 volt between the signal circuit terminal B and ground.
    7. ⇒If not within the specified range, test the signal circuit for a short to voltage.
  7. Test for less than 1.0 ohm between the signal circuit terminal B at the sensor harness connector and terminal 6 at the PPS harness connector.
    8. ⇒If greater than the specified range, test the signal circuit for an open/high resistance.
  8. If all circuits test normal, test or replace the inflatable restraint PPS sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  SIR/SRS Wiring Repairs
    •  Control Module References for PPS replacement, setup, and programming