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 Descriptor

DTC 024: PPS Ignition 1 Voltage Performance

### Circuit/System Description

The passenger presence system (PPS) module has an ignition 1 voltage input. The PPS continually monitors itself for faults. If the voltage on this circuit falls below a certain threshold, the PPS will set DTC 024. When the PPS detects this DTC within the PPS it will notify the customer of the enable/disable status by turning ON 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 non GMLAN 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 turn the AIR BAG indicator ON.

### Conditions for Running the DTC

The PPS detects ignition 1 voltage is less than 8 volts for 500 milliseconds.

### Conditions for Setting the DTC

• | The PPS detects the voltage at the passenger seat belt tension retractor sensor signal is less than 0.05 volt or greater than 4.5 volts for 500 milliseconds.

• | The PPS detects the voltage at the passenger seat belt tension retractor 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 passenger seat belt tension retractor 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 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.

### 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.

### Diagnostic Aids

The PPS will set DTC 024 as a history code only, when the ignition voltage has fallen below 8 volts. This is a normal condition for DTC 024 and it should be diagnosed as a current DTC.

### 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.

• | The PPS module

• | The PPS wiring harness connector

1. Ignition OFF, disconnect the PPS module connector.
2. Test the PPS ground circuit for an open or high resistance. Verify that an open or high resistance does not exist.

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

3. Test the PPS ignition 1 voltage circuit for a short to ground, an open, or high resistance. Verify that a short to ground, an open, or high resistance does not exist.

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

4. Reconnect all PPS components. Use the scan tool to clear all PPS DTCs. Refer to Passenger Presence System Flash Code Procedures . Verify DTC 024 does not exist.

⇒ | If DTC 024 resets, check for proper voltage level to PPS.

### 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