GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Saturn 🢒 2007 🢒 AURA 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC 056

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 provide an overview of each diagnostic category.

DTC Descriptor

DTC 056: PPS Internal System Fault

Circuit/System Description

The inflatable restraint passenger presence system (PPS) continuously monitors for critical faults. If the PPS determines either a fault internal to the electronic control unit (ECU), sensor mat, or a circuit fault between the PPS module and the passenger heated seat control module, the PPS will set DTC 056, illuminate the PASSENGER AIRBAG status indicator to OFF, and notify the sensing and diagnostic module (SDM) of a fault in the PPS through a non class 2 communications circuit. Other DTCs like DTC 034 or DTC 036 may set along with DTC 056. Diagnose all current DTCs before diagnosing DTC 056. The PPS, heated seat element, and seat bottom cushion is only service as a complete kit, which is a calibrated system and must be replaced as a complete unit. If a service kit was installed, DTC 056 will be set current and the Rezeroing Procedure must be performed before the DTC can be cleared.

Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

Conditions for Setting the DTC
    • PPS ECU internal electronic fault
    • PPS Sensor mat internal electronic fault
    • PPS Service kit was installed
    • Circuit fault between PPS module and the passenger heated seat control module

Action Taken When the DTC Sets
    • The PPS will set a DTC 056, and then communicate with the SDM via a dedicated serial data circuit.
    • The SDM will set DTC B0081.
    • The SDM disables the I/P module deployment loop.
    • The PPS will illuminate the OFF indicator of the PASSENGER AIRBAG ON/OFF indicator.
    • The SDM requests the instrument panel cluster (IPC) to illuminate the AIR BAG indicator.

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.

Diagnostic Aids

DTC 034 or DTC 036 may set along with DTC 056. Diagnose all current DTCs before diagnosing DTC 056. This DTC 056 indicates that you have installed a service kit or have an internal fault to the ECU or sensor mat.

Reference Information

Schematic Reference

SIR Schematics

Connector End View Reference

SIR Connector End Views

Electrical Information Reference

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

Circuit/System Verification

Verify that the seat cushion is dry.

⇒If seat cushion is wet, allow cushion to dry for 48 hours using a fan. Refer to Front Seat Cushion Cover and Pad Replacement.

Circuit/System Testing
  1. Ignition ON, use the scan tool. Go to the PPS menu, then retrieve the DTCs. Refer to Passenger Presence System Flash Code Procedures. Verify DTC 034 or DTC 036 does not set.
    2. ⇒If either DTC 034 or DTC 036 sets then refer to Diagnostic Trouble Code (DTC) List - Vehicle.
  2. Check to see if the PPS has been replaced. Verify the correct PPS has been installed.
    3. ⇒If the incorrect PPS was installed replace with the correct PPS. Then perform the Passenger Presence System Rezeroing.
  3. If equipped, ignition ON, verify that the passenger heated seat operates properly.
    4. ⇒If the heated seat does not operate, refer to Heated Seat Inoperative.
  4. If equipped, ignition OFF, disconnect the PPS module C1 harness connector.
  5. If equipped, ignition ON, heated seat ON, verify that a test lamp illuminates between the passenger heated seat back low reference circuit terminal 10 and ground.
    6. ⇒If the test lamp does not illuminate, test the low reference circuit for a short to ground or an open/high resistance.
  6. Perform the Passenger Presence System Rezeroing and recheck for DTC 056. Verify that DTC 056 does not reset.
    7. ⇒If DTC 056 sets, then replace the PPS and rezero.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

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