GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Spark 🢒 Restraints 🢒 SIR 🢒 DTC 025

Circuit Description

When the ignition switch is turned ON, the sensing and diagnostic module (SDM) will perform tests to diagnose any malfunctions within itself.

After passing these tests, the SDM will check the warning lamp circuit. The SDM constantly measures the voltage at the warning lamp output in order to determine if the lamp is ON or OFF at the correct time.

Conditions for Setting the DTC
    • The lamp is ON when it should be OFF.
    • The lamp is OFF when it should be ON.

Diagnostic Aids

When the warning lamp operates correctly, the warning lamp turns ON for approximately 4 seconds after the ignition is first switched ON, and then the warning lamp turns OFF.

When the warning lamp operates incorrectly, the warning lamp continues to blink 4 times per second, demonstrating that the SDM is faulty and must be replaced.

Step

Action

Values

Yes

No

Caution: Refer to Battery Disconnect Caution in the Preface section.

Caution: This vehicle is equipped with Supplemental Inflatable Restraint (SIR). Refer to the Cautions in the On-Vehicle Service and the SIR Component and Wiring Location view in the Supplemental Inflatable (SIR) System before any performing service on or around SIR components or wiring. Failure to follow the Cautions could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs.

Caution: Refer to SIR Special Tool Caution in the Preface section.

1

Turn the ignition ON.

Is the warning lamp constantly ON?

--

Go to Step 2

Go to Step 9

2

Make sure the SDM connector is attached correctly.

Does the warning lamp turn OFF?

--

Go to Diagnostic Aids

Go to Step 3

3
  1. Check for indications of the diagnostic trouble code (DTC) other than the code 25.

    2. Refer to the appropriate DTC charts and repair each additional problem.

  2. Perform the diagnostic system check.

Does the scan tool still indicate DTC 025?

--

Go to Step 4

System OK

4

Check for a short to ground between the SDM and the warning lamp using the following method:

  1. Turn the ignition OFF.
  2. Disconnect the connector C208.
  3. Connect 1 ohmmeter lead to ground.
  4. Touch the other ohmmeter lead to the terminal 3 of the connector C208 on the instrument harness side. Refer to Diagnostic Illustration 14 in SIR Diagnostic Illustrations .

Does the ohmmeter indicate the specified value?

∞

Go to Step 6

Go to Step 5

5

Repair the short to ground in the instrument harness.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

6
  1. The connector C208 remains disconnected.
  2. One lead of the ohmmeter remains connected to ground.
  3. Move the ohmmeter lead at the connector C208 to the SDM side of the connector. Refer to Diagnostic Illustration 13 in SIR Diagnostic Illustrations .

Does the ohmmeter indicate the specified value?

∞

Go to Step 7

Go to Step 8

7

Replace the SDM.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

8
  1. Disconnect the negative battery cable.
  2. Replace the SIR wiring harness.
  3. Perform the diagnostic system check.

Does DTC 025 still show as a current fault?

--

Go to Step 5

System OK

9

Check the fuse F1.

Is the fuse F1 blown?

--

Go to Step 10

Go to Step 11

10
  1. With the connector C208 temporarily disconnected, check for a short to ground between the fuse F1 and the warning lamp.
  2. Make a repair, if needed.
  3. Replace the fuse F1.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

11
  1. Turn the ignition ON.
  2. Using a multimeter, check the voltage at the fuse F1.

Does the multimeter show the specified value?

11-14 V

Go to Step 13

Go to Step 12

12

Repair the open power supply circuit for the fuse F1.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

13
  1. Disconnect the connector C208.
  2. Turn the ignition ON.
  3. Using a multimeter, check the voltage on the instrument harness side of the terminal 3 of the connector C208.

Does the multimeter show the specified value?

11-14 V

Go to Step 15

Go to Step 14

14
  1. Check the warning lamp bulb.
  2. Replace the warning lamp bulb, if needed.
  3. If the bulb is good, repair the open circuit between the fuse F1 and the terminal 3 of the connector C208.

Is the repair complete?

--

Go to Diagnostic System Check - SIR

--

15
  1. Disconnect the negative battery terminal.
  2. Wait at least 1 minute before proceeding.
  3. Replace the SIR wiring harness.

Is the repair complete?

--

System OK

--