B1209 - Frontal Collision Detection

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
Comments  |  Add Comment

B1209 Possible Causes

  • Faulty Air Bag Diagnosis Sensor Unit (ACU)
  • Air Bag Diagnosis Sensor Unit (ACU) harness is open or shorted
  • Air Bag Diagnosis Sensor Unit (ACU) circuit poor electrical connection

First diagnose B1209 code

    Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

B1209 Tech Notes

After a front collision, all the deployed components and the Air Bag Diagnosis Sensor Unit (ACU) must need to be replaced. If there is no collision, then the problem is with the Air Bag Diagnosis Sensor Unit (ACU)

Cost of diagnosing the B1209 code

    Labor: 1.0

    The cost of diagnosing the B1209 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

B1209 Possible Symptoms

  • Air Bag Warning Light ON

B1209 Description

Detects component damage resulting from a front collision, blinks or illuminates the air bag warning lamp to

inform the driver. The air bag and seat belt pre-tensioners for driver and front seat passenger are operated by the decision of the Air Bag Diagnosis Sensor Unit (ACU) out signal transmitted because of the frontal collision.

The Frontal Collision Detection consists of crash zone sensor, Air Bag Diagnosis Sensor Unit (ACU), air bags and seat belt pre-tensioners for driver and front passenger.

OBDII Code B1209 - Frontal Collision Detection - AutoCodes.com

B1209 More Information

Need more information on how to fix the B1209 code?
Get Access to Factory Service Manuals

B1209 Information for specific makes

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

  • Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
  • Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
  • Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
  • Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.
Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

Need more help?

Get the B1209 code diagnosed by a professional: Find a repair shop in your area

Related Information

B1209 Comments

Help us improve AutoCodes.com. Leave a comment below or tell us if the information above help you fix the code. What are the symptoms on your vehicle for the B1209 code? Have you replaced any parts?
Any information is appreciated. Thanks
Top ⇧