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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Camaro 🢒 Restraints 🢒 SIR 🢒 AIR BAG Warning Lamp Circuit Malfunction

Object Number: 550470 Size: SF
SIR Components
SIR Schematic
Handling ESD Sensitive Parts Notice
SIR Caution
Handling ESD Sensitive Parts Notice
Class 2 Serial Data Line
Instrument Cluster Gauges

Circuit Description

The ignition switch supplies ignition 1 voltage to the inflatable restraint sensing and diagnostic module (SDM) at terminal A1 using the AIR BAG Fuse. The ignition switch also supplies ignition 1 voltage to the instrument cluster. The AIR BAG warning lamp is controlled by the SDM via Class 2 serial data. When the ignition switch is first turned ON, the instrument cluster flashes the AIR BAG warning lamp seven times. Next, the SDM performs tests on the SIR system then commands the instrument cluster to turn OFF the AIR BAG warning lamp after it has flashed seven times. If the ignition 1 voltage is outside of the normal operating voltage range (9-16 V), the SDM will command the instrument cluster to turn ON the AIR BAG warning lamp with no DTCs present.

Diagnostic Aids

The loss of serial data communication between the SDM and the instrument cluster will cause the AIR BAG warning lamp to come ON solid. Refer to A Diagnostic System Check - Data Link Communications in Data Link Communications.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This step checks to see if the AIR BAG warning lamp flashes seven times when the ignition is turned ON.

    2.

  2. This step checks to see if DTC U1088 is present in the instrument cluster.

    3.

  3. This step checks to see if the AIR BAG warning lamp is being commanded ON.

    4.

  4. This step checks to see if the ignition voltage to the SDM is more than 9 V.

    5.

  5. This step determines if the ignition voltage to the SDM is more than 16 V or if there is a malfunctioning SDM.

    6.

  6. This step checks to see if the SDM wiring harness connector exhibits signs of corrosion, terminal damage, or poor connections.

    7.

  7. This step checks to see if there is an open or a high resistance in the B+ feed circuit to the SDM.

    8.

  8. This step checks to see if there is an open or a high resistance in the B+ feed circuit to the AIR BAG Fuse.

    9.

  9. This step determines if there is an open or a high resistance in the SDM ground circuit or if there is a malfunctioning SDM.

AIR BAG Warning Lamp Circuit Malfunction

Step

Action

Value(s)

Yes

No

1

Did you perform the SIR Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - SIR

2

Did you perform the Instrument Cluster Diagnostic System Check?

--

Go to Step 3

Go to Diagnostic System Check - Instrument Cluster in Instrument Panel, Gauges and Console

3

  1. Turn OFF the ignition.
  2. Note the AIR BAG warning lamp while turning ON the ignition.

Does the AIR BAG warning lamp flash seven times?

--

Go to Step 5

Go to Step 4

4

Replace the instrument cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gauges and Console.

Did you complete the repair?

--

Go to Step 18

--

5

  1. Install a scan tool.
  2. Attempt to communicate with the instrument cluster.
  3. Use the scan tool to request the instrument cluster DTC display.

Does the scan tool indicate that DTC U1088 is current?

--

Go to Scan Tool Does Not Communicate with Class 2 Data Line in Data Link Communications

Go to Step 6

6

Use the scan tool to request the instrument cluster data list display.

Is the AIR BAG warning lamp being commanded ON?

--

Go to Step 7

Go to Step 4

7

  1. Attempt to communicate with the inflatable restraint sensing and diagnostic module (SDM).
  2. Use the scan tool to request the SIR data list display.

Is the ignition voltage displayed on the scan tool more than the specified value?

9 V

Go to Step 8

Go to Step 9

8

Is the ignition voltage displayed on the scan tool more than the specified value?

16 V

Go to Charging System Test in Engine Electrical

Go to Step 17

9

  1. Turn OFF the ignition.
  2. Disconnect the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .
  3. Inspect the SDM wiring harness connector for the following conditions:
    4. • Corrosion
    • Damaged terminals
    • Poor connections/terminal tension

Does the SDM wiring harness connector exhibit any sings of corrosion, terminal damage, or poor connections?

--

Go to Step 10

Go to Step 11

10

Replace the SDM wiring harness connector. Refer to Connector Repairs in Wiring Systems.

Did you complete the repair?

--

Go to Step 18

--

11

  1. Remove the AIR BAG Fuse.
  2. Disconnect inline connectors C218 and C219.
  3. Use the J 39200 Digital Multimeter (DMM) to measure the resistance between the output side of the AIR BAG Fuse and terminal A1 of the SDM wiring harness connector.

Does the resistance measure less than the specified value?

2 ohms

Go to Step 13

Go to Step 12

12

Locate and repair an open or a high resistance in the B+ feed circuit to the SDM.

Did you complete the repair?

--

Go to Step 18

--

13

  1. Turn ON the ignition, with the engine OFF.
  2. Use the J 39200 to measure the voltage between the input side of the AIR BAG Fuse and a known good ground.

Does the voltage measure near the specified value?

12 V

Go to Step 15

Go to Step 14

14

Locate an open or a high resistance in the B+ feed circuit to the AIR BAG Fuse.

Did you complete the repair?

--

Go to Step 18

--

15

Use the J 39200 to measure the resistance between terminal A18 of the SDM wiring harness connector and a known good ground.

Does the resistance measure less than the specified value?

2 ohms

Go to Step 17

Go to Step 16

16

Locate and repair an open or a high resistance in the SDM ground circuit.

Did you complete the repair?

--

Go to Step 18

--

17

Replace the SDM. Refer to Inflatable Restraint Sensing and Diagnostic Module Replacement .

Did you complete the repair?

--

Go to Step 18

--

18
  1. Reconnect all SIR and instrument cluster components.
  2. Verify that all components and connectors are properly mounted.
  3. Turn On the ignition, with the engine OFF.
  4. Use the scan tool in order to clear the DTCs.

Did you complete the action?

--

Go to Diagnostic System Check - SIR

--