B0079 OBD-II Trouble Code: SRS Airbag Sensor Circuit Fault

The B0079 trouble code is a Body (B) diagnostic trouble code related to the Supplemental Restraint System (SRS). This code indicates a fault in an airbag-related sensor circuit. The exact definition of B0079 can vary depending on the vehicle manufacturer, year, and model.

B0079 Code Meaning

B0079 commonly relates to an SRS sensor circuit problem, such as a seat position sensor circuit or another restraint system sensor. The SRS control module continuously monitors sensor signals to calculate the correct airbag deployment strategy.

When the module detects an abnormal signal, open circuit, short circuit, or incorrect resistance value, it stores B0079 and turns on the airbag warning light.

Common Symptoms of B0079

• SRS airbag warning light stays ON
• Airbag system may become disabled
• Incorrect seat position information in live data
• Stored airbag fault after collision repair
• Intermittent warning light

Possible Causes of B0079

• Damaged wiring under the seat
• Loose or disconnected SRS connector
• Corrosion inside electrical connectors
• Faulty seat position sensor
• High resistance in sensor wiring
• SRS control module problem

B0079 SRS Circuit Diagram

SRS Control Module
(Airbag ECU)

⬇

Signal Wire
Sensor Communication

⬇

Seat Position Sensor
or SRS Sensor

Reference
Voltage

Ground
Circuit

Note: SRS wiring, pin numbers, sensor type, and voltage values vary between vehicle manufacturers. Always use the correct factory wiring diagram before testing.

B0079 Diagnostic Procedure

Proper diagnosis of B0079 requires an SRS-capable scan tool. A basic engine OBD scanner may not access airbag system data. Always follow safety procedures before working on SRS components.

Step 1: Check SRS Trouble Codes

Connect the diagnostic scanner and read all stored SRS codes. Additional codes may identify whether the problem is related to a sensor, wiring, or the SRS control module.

Step 2: Inspect SRS Connectors

• Inspect connectors under the seats.
• Check for loose locking mechanisms.
• Look for damaged terminals or corrosion.
• Inspect wiring for stretching or cuts.

Step 3: Check Live Data

If the scan tool supports SRS live data, monitor the related sensor values. Move the seat slowly forward and backward and observe whether the sensor value changes smoothly.

Example Live Data

Seat Position Sensor:

Seat Forward Position ➜ Lower Sensor Value

Seat Rear Position ➜ Higher Sensor Value

Normal Signal: Smooth change without sudden jumps or missing data.

Electrical Testing (General Method)

SRS circuits are manufacturer specific. Do not test airbag igniters directly with a normal multimeter unless the service manual allows it.

SRS Module

⬇

Signal Circuit

⬇

Sensor

⬇

Ground Return

Common Repairs for B0079

• Repair damaged wiring harness
• Secure loose SRS connectors
• Replace faulty sensor if confirmed
• Repair communication problems with SRS module
• Clear the code after repair and perform a system check

SRS Safety Warning

Never apply external power to airbag components. Incorrect testing methods can cause accidental deployment or damage to the SRS system.

Related SRS Trouble Codes

B0075

SRS sensor circuit related fault. Meaning depends on vehicle manufacturer.

B0076

Airbag sensor circuit range or performance problem.

B0077

SRS sensor circuit low voltage or electrical fault.

B0078

SRS sensor circuit high signal or wiring issue.

B0080

Additional SRS sensor circuit fault depending on vehicle application.

B0079 FAQ

What does B0079 mean?

B0079 indicates a fault in an SRS airbag-related sensor circuit. The exact component depends on the vehicle manufacturer and model.

Is it safe to drive with B0079?

The vehicle may operate normally, but the airbag system may not function correctly during a collision. The problem should be diagnosed and repaired.

Can B0079 be caused by wiring?

Yes. Damaged wiring, loose connectors, corrosion, or high resistance can cause B0079 without a failed sensor.

Can I clear B0079 with an OBD scanner?

A scanner that supports SRS systems can clear the code after the repair. If the fault remains, the code will return.

Where is the B0079 sensor located?

The location varies by vehicle. It may be inside the seat, under the seat, near an airbag module, or in another restraint system location.

OBDSpark Diagnostic Tip

Always identify the exact vehicle year, make, and model before diagnosing B0079. SRS circuits use different designs, connectors, and sensor strategies between manufacturers.

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