GM Service Manual Online
For 1990-2009 cars only

Object Number: 238645  Size: SF
SIR Components
SIR Schematics
SIR Caution
SIR Caution
Handling ESD Sensitive Parts Notice

Circuit Description

When you first turn the ignition switch to the ON position, the inflatable restraint Sensing and Diagnostic Module (SDM) performs tests to diagnose critical malfunctions within itself. The SDM monitors the voltages at DRIVER SIDE LOW terminal 9 and PASSENGER SIDE LOW terminal 8 to detect shorts-to-B+ in the inflator module circuits.

Conditions for Setting the DTC

The SDM detects a short to battery voltage in the passenger deployment loop.

Action Taken When the DTC Sets

    â€¢ The SDM sets a Diagnostic Trouble Code.
    â€¢ The SDM turns ON the AIR BAG warning lamp.

Conditions for Clearing the DTC

All DTCs are cleared with each ignition cycle.

Diagnostic Aids

A short to B+ in the inflatable restraint IP module circuit can cause an intermittent condition. Inspect the YEL/RED and YEL/GRN wires leading to the IP module carefully for cut or chafed wires.

Test Description

  1. This test checks for a short to voltage in the passenger side high circuit.

  2. This test checks for a short to voltage in the passenger side low circuit.

  3. This test determines if the malfunction is caused by the SDM.

  4. This test determines if the malfunction is caused by the inflatable restraint instrument panel module.

Step

Action

Value(s)

Yes

No

1

Was the SIR Diagnostic System Check performed?

--

Go to Step 2

Go to SIR Diagnostic System Check

2

  1. Turn the ignition switch to the OFF position.
  2. Disconnect the inflatable restraint Sensing and Diagnostic Module (SDM).
  3. Disconnect the inflatable restraint IP module.
  4. Turn the ignition switch to the ON position.
  5. Measure the voltage at the seat module harness connector between terminal 1 and ground.

Is the voltage measured greater than the specified value?

0 V

Go to Step 8

Go to Step 3

3

Measure the voltage at the inflatable restraint IP module harness connector between terminal 2 and ground.

Is the voltage measured greater than the specified value?

0 V

Go to Step 9

Go to Step 4

4

  1. Turn the ignition switch to the OFF position.
  2. Connect the SDM.
  3. Connect a jumper wire between terminals 1 and 2 of the inflatable restraint IP module harness connector.
  4. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
  5. Clear SIR DTCs.
  6. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
  7. Check for SIR DTCs.

Is DTC 52 present?

--

Go to Step 6

Go to Step 5

5

  1. Turn the ignition switch to the OFF position.
  2. Connect the inflatable restraint IP module connector.
  3. Turn the ignition switch to ACC or ON and wait 20 seconds.
  4. Clear SIR DTCs.
  5. Turn the ignition switch to the ACC or ON position and wait 20 seconds.
  6. Check for SIR DTCs.

Is DTC 52 present?

--

Go to Step 7

Go to Step 10

6

Replace the inflatable restraint Sensing and Diagnostic Module (SDM). Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Are all the repairs complete?

--

Go to Step 11

--

7

Replace the inflatable restraint IP module. Refer to Inflatable Restraint Instrument Panel Module Replacement .

Are all the repairs complete?

--

Go to Step 11

--

8

Repair a short to voltage in the YEL/RED wire between the IP module and the SDM. Refer to Wiring Repair in this section.

Are all the repairs complete?

--

Go to Step 11

--

9

Repair a short to voltage in the YEL/GRN wire between the IP module and the SDM. Refer to Wiring Repair in this section.

Are all the repairs complete?

--

Go to Step 11

--

10

An intermittent exists in the passenger deployment loop. Refer to Diagnostic Aids.

Are all the repairs complete?

--

Go to Step 11

--

11

Reconnect all SIR components. Make sure all components are properly mounted.

Have all the SIR components been reconnected and properly mounted?

--

Go to SIR Diagnostic System Check

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