For 1990-2009 cars

### 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 Descriptors

DTC 1049: PPS System Fault
DTC 1050: PPS System Fault

### Circuit/System Description

The passenger presence system (PPS) is used to monitor the pressure profile of any occupant that is sitting in the front outboard passenger seat and communicates the profile classification to the sensing and diagnostic module (SDM). The SDM will either enable or suppress the deployment of the instrument panel (I/P) module based on the profile classification of the occupant. If the PPS detects that the vehicle voltage is too low or high, the PPS will then set a DTC within the PPS, then the PPS will communicate to the SDM through a non GMLAN communications circuit that a PPS fault is present. The SDM will then set DTC B0081 indicating a problem within the PPS.

### Conditions for Running the DTC

Ignition voltage is between 9-16 volts.

### Conditions for Setting the DTC

The PPS has detected supply battery voltage too low or too high.

### Action Taken When the DTC Sets

• | The PPS will set a DTC, and then communicate with the SDM via non GMLAN circuit.

• | The SDM will set DTC B0081.

• | The SDM disables the I/P module deployment loop.

• | The PPS will turn ON the passenger air bag status OFF indicator.

• | The SDM commands the AIR BAG indicator ON via serial data communications.

### Conditions for Clearing Away the DTC

• | When conditions for the DTC is set no longer exists, use CLEAR DTC function of the scan tool to clear the DTC.

• | After 255 consecutive warm-up cycles without failure, the DTC will be cleared.

### Diagnostic Aids

DTC 1049 is an indication that the supply battery voltage (ignition 1) to the PPS is too low and could be from corrosion. DTC 1050 is an indication that the supply battery voltage (ignition 1) to the PPS is too high.

### 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 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. Engine running, use the scan tool. Go to the PPS menu, then retrieve the DTCs. Verify DTC 1050 does not set.

⇒ | If DTC 1050 is set as current, refer to Charging System Test .

2. Ignition ON, engine OFF, use the scan tool and check for DTC 1049. Verify DTC 1049 is set as current.

⇒ | If DTC 1049 is set as history clear codes.

3. Ignition OFF, disconnect the PPS module connector. Refer to PPS Replacement in Repair Instructions for location of connector.
4. Test the PPS ignition 1 circuit for high resistance or short to ground. Verify no high resistance or short to ground exist.

⇒ | If any of the above conditions are found, make the appropriate repair.

5. Test the PPS ground circuit for high resistance.

Verify no high resistance exists.

⇒ | If high resistance is found make the appropriate repair.

6. Use the scan tool and perform Passenger Presence System Preload Test , and then request codes. Verify DTC 1049 does not set.

⇒ | If DTC 1049 resets, replace the PPS.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Refer to Control Module References for PPS replacement, setup and programming.