Circuit 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, turn the passenger air bag 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.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC 056 PPS Internal System Fault
Conditions for Running the DTC
Ignition 1 voltage is within the normal operating voltage range.
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, then communicate with the SDM via non class 2 circuit. |
| • | The SDM will set DTC B0092. |
| • | The SDM disables the instrument panel module (IPM) deployment loop. |
| • | The PPS will turn ON the passenger air bag status OFF indicator. |
| • | 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. |
| • | If service kit was installed, you performed the rezeroing procedure with a scan tool. |
Diagnostic Aids
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 Replacement .
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.
Test Description
The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: SIR Schematics Connector End View Reference: SIR Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
Does DTC 034 or DTC 036 set as current? | Go to Step 3 | ||
3 | Was a new passenger presence system (PPS) service kit installed? | Go to Step 4 | Go to Step 5 |
4 | When a PPS service kit has been installed you must perform the rezeroing procedure. Refer to Control Module References for replacement, setup, and programming. Did you complete the rezeroing procedure? | Go to Step 5 | -- |
5 |
Does DTC 056 reset? | Go to Step 6 | Go to Step 7 |
6 |
Important: The PPS, heated seat element, and seat bottom cushion is only serviced as a complete kit. Did you complete the replacement? | Go to Step 7 | -- |
7 |
Does the DTC reset? | Go to Step 2 | System OK |
