DTC 056

DTC 056

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.

DTC Descriptor
DTC 056
- Internal System Fault

Circuit/System Description

The inflatable restraint Passenger Presence System (PPS) continuously monitors for critical faults. If the PPS determines there is a fault internal to the electronic control unit (ECU) or sensor mat, the PPS will set DTC 056, illuminate the passenger air bag status OFF indicator 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.

Action Taken When the DTC Sets

* The PPS will set a DTC 056, and then communicate with the SDM via non class 2 circuit.
* The SDM will set DTC B0092.
* The SDM disables the instrument panel (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 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 100 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 ([1][2]Air Bag Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

SIR System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition ON, use the scan tool. Retrieve the DTCs. Refer to Passenger Presence System Flash Code Procedures (Passenger Presence System Flash Code Procedures). Verify DTC 032, DTC 034 or DTC 036 are not set.

• If either DTC 032, DTC 034 or DTC 036 is set, then refer to Diagnostic Trouble Code (DTC) List - Vehicle (Diagnostic Trouble Code Descriptions).

2. If the PPS has been replaced. Verify the correct PPS has been installed.

• If the incorrect PPS was installed, replace with the correct PPS and perform the Passenger Presence System Rezeroing (Programming and Relearning).

3. Ignition ON, verify that the rezeroing procedure was performed successfully and that DTC 056 is not set as current. Refer to Passenger Presence System Flash Code Procedures (Passenger Presence System Flash Code Procedures).

• If DTC 0056 is set as current, replace the PPS.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* SIR/SRS Wiring Repairs (Component Tests and General Diagnostics)
* Control Module References (Programming and Relearning) for SDM and PPS replacement, setup, and programming