Source voltage drop

The srs is equipped with a voltage-increase circuit (dc-dc converter) in the center airbag sensor in case the source voltage drops.

When the source voltage drops, the voltage-increase circuit (dc-dc converter) functions to increase the voltage of the srs to a normal working level.

A malfunction in this circuit is displayed differently from other codes, in the fact that no dtcs are recorded. With a normal system code present, the source voltage drop is indicated when the srs warning light comes on.

A malfunction in this circuit is not recorded in the center airbag sensor .

The srs warning light automatically goes off when the source voltage returns to normal.

1. Check wire harness (center airbag sensor assembly - battery)

1. 1
   Turn the ignition switch off.
2. 2
   Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
3. 3
   Disconnect the e45 connector from the center airbag sensor .
4. 4
   Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
5. 5
   Measure the voltage of the wire harness side connectors.

Standard voltage

2. Check wire harness (center airbag sensor assembly - body ground)

1. Measure the resistance of the wire harness side connectors.

Standard resistance

2. Check wire harness (center airbag sensor assembly - body ground)

1. Measure the resistance of the wire harness side connectors.

Standard resistance

1. 1
   Check srs warning light
2. 2
   Turn the ignition switch off.
3. 3
   Disconnect the negative (-) terminal cable from the battery, and wait for at least 90 seconds.
4. 4
   Connect the e45 center airbag sensor connector.
5. 5
   Connect the negative (-) terminal cable to the battery, and wait for at least 2 seconds.
6. 6
   Turn the ignition switch on, and wait for at least 6 seconds.
7. 7
   Operate all components of the electrical system (defogger, wiper, headlight, heater, blower, etc.) And check that the srs warning light does not come on.