GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The inflatable restraints 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-class 2 communications circuit that a PPS fault is present. The SDM will then turn the AIR BAG indicator ON, and set DTC B0092 or B0098 indicating a problem within the PPS and will suppress the deployment of the instrument panel (I/P) module.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC 024 PPS Ignition 1 Voltage Performance

Conditions for Running the DTC

Ignition 1 voltage is within the normal operating voltage range.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

    • The PPS will set a DTC 024, then communicate with the SDM via non-class 2 circuit.
    • The SDM will set DTC B0092 or B0098.
    • 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 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.

Diagnostic Aids

The following can cause an intermittent condition:

    • A short in the ignition 1 voltage circuit
    • An open or high resistance in the ignition 1 voltage circuit

Thoroughly inspect the wiring and the connectors. An incomplete inspection of the wiring and the connectors may result in a misdiagnosis, causing a part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

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.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step inspects the PPS module connector.

  2. This step inspects the main seat harness connector.

  3. This step tests the PPS ground circuit for an open or high resistance.

  4. This step tests the PPS ignition 1 voltage circuit for a short to ground, an open, or high resistance.

Step

Action

Yes

No

Schematic Reference: SIR Schematics

Connector End View Reference: SIR Connector End Views and Power Seat Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF the ignition.
  2. Disconnect the passenger presence system (PPS) module connector. Refer to Control Module References for replacement, setup, and programming.
  3. Inspect the PPS module connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 3

3

  1. Disconnect the main seat harness connector located under the RF seat.
  2. Inspect both halves of the connector for corrosion or damage. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 4

4

Test the PPS ground circuit for an open or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 5

5

Test the PPS ignition 1 voltage circuit for a short to ground, an open, or high resistance. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 6

6

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

Did you complete the replacement?

Go to Step 7

--

7

  1. Reconnect all supplemental inflatable restraint (SIR) and PPS system components.
  2. Verify that all components, connectors, and connector position assurances (CPAs) are properly mounted.
  3. Use the scan tool in order to clear the SIR and PPS DTCs.
  4. Rezero the PPS. Refer to Control Module References for replacement, setup, and programming.
  5. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK