Fault code B1266 – a step-by-step guide to diagnosing and fixing it

The meaning of error code B1266 – Servo Motor Airintake Left Circuit Failure

B1266: Causes, signs and repairs

Error code B1266 is displayed and the check engine light is on - what does this mean?

The DTC B1266 is recognized by the OBD/EOBD system and indicates a problem with the airbag side sensor or its circuit. This fault code mainly affects the vehicle's safety system and can have slightly different meanings for different manufacturers, but generally refers to faults in the side airbag system.

What causes can this fault code have?

Defective side airbag sensor
Damaged wiring to the airbag system
Corroded or loose plug connections
Faulty airbag control unit
Mechanical damage to the sensor cable
Defective earth connection in the airbag circuit
Short circuit in the sensor cable
Overvoltage in the airbag system

What symptoms occur in parallel with fault code B1266?

Airbag warning light: The airbag indicator light in the dashboard lights up continuously or flashes
Safety system failure: The side airbag system may not be functional
Fault messages: Warning messages relating to the airbag system appear on the display
System diagnostic problems: OBD scanner displays additional airbag-related fault codes
Electronic malfunctions: Other safety systems may be impaired

How to fix the problem of error code B1266?

The repair of error code B1266 requires a systematic approach and should be carried out by qualified personnel.
Perform a complete system diagnosis: Use a professional OBD scanner to read all fault codes, clear temporary codes and perform a full airbag system check
Check wiring and plug connections: Check all wiring connections to the side airbag sensor for damage, clean corroded contacts and ensure tight connections
Replace side airbag sensor: Professionally remove the defective sensor, install a new OEM-compatible sensor and reprogram the system
Check and replace airbag control unit: Test the control unit with diagnostic equipment, replace if defective and perform a complete re-code
Repair ground connections: Locate defective ground connections, thoroughly clean contact points and restore proper grounding

FAQ - Frequently asked questions about DTC B1266

Can I continue driving with fault code B1266?

It is possible to continue driving, but not recommended, as the side airbag may not work. This could lead to serious injuries in the event of an accident. Have the fault rectified as soon as possible.

How much does it cost to repair error code B1266?

The repair costs vary between 150-800 euros, depending on the cause. A defective sensor costs around 200-400 euros, while replacing the control unit can cost up to 800 euros, plus labor.

How long does it take to repair trouble code B1266?

The repair time depends on the cause. Simple cable repairs take 1-2 hours, while sensor replacement takes 2-4 hours. Control unit replacement can take a whole day.

Can error code B1266 be caused by moisture?

Yes, moisture can cause corrosion on plug connections and trigger the EOBD error code B1266. The sensors are particularly susceptible to moisture damage in the door areas.

Is the DTC B1266 manufacturer-specific?

The B1266 code is largely standardized, but may have slightly different meanings for different manufacturers. BMW, Mercedes and Audi use similar definitions for side airbag sensor faults.

Can other systems be affected by fault code B1266?

Yes, as modern vehicles have networked safety systems, fault code B1266 can also affect ESP, ABS or other assistance systems. A complete system diagnosis is therefore important.

Vehicles in which fault code B1266 occurs most frequently

Fault code B1266 is an airbag system-related DTC and can affect various side airbag sensors, but is most common in the following vehicles:

BMW: 3 Series (E90, E91, E92), 5 Series (E60, E61), X3 (E83), X5 (E70) (2004-2013)
Mercedes-Benz: C-Class (W204), E-Class (W211, W212), S-Class (W221), ML-Class (W164) (2005-2014)
Audi: A4 (B7, B8), A6 (C6, C7), Q5 (8R), Q7 (4L) (2005-2015)
Volkswagen: Passat (B6, B7), Tiguan (5N), Touareg (7L, 7P) (2006-2016)
Ford: Focus (MK2, MK3), Mondeo (MK4), Kuga (MK1) (2007-2014)
Opel: Insignia (A), Astra (J), Zafira (B) (2008-2016)
Peugeot: 308 (T7), 508 (8D), 3008 (0U) (2009-2017)
Renault: Megane (III), Laguna (III), Scenic (III) (2008-2015)

If code B1266 occurs in your vehicle, you should visit a specialist workshop immediately, as this is a safety-critical system. Airbag systems are complex and require specialized diagnostic equipment and expertise to repair safely. Never attempt to repair airbag components yourself, as this can lead to unintentional deployment or malfunction.

How to change front wheel bearing on MERCEDES-BENZ M W163 TUTORIAL | AUTODOC

151K views

Published on: 26/07/2018
How to change fuel filter BMW 3 (E90) [TUTORIAL AUTODOC]

241K views

Published on: 17/04/2019
How to change Front wheel bearing on VW GOLF 4 TUTORIAL | AUTODOC

177K views

Published on: 26/07/2018
How to change a rear brake pads FORD FOCUS 3 TUTORIAL | AUTODOC

169K views

Published on: 27/07/2018
How to change pollen filter / cabin filter on AUDI A6 (C6) [TUTORIAL AUTODOC]

150K views

Published on: 25/10/2019
How to change engine thermostat on PEUGEOT 207 [TUTORIAL AUTODOC]

147K views

Published on: 09/12/2020
How to change fuel filter NISSAN X-TRAIL T30 TUTORIAL | AUTODOC

139K views

Published on: 27/07/2018
How to change front wheel bearing TOYOTA YARIS XP10 TUTORIAL | AUTODOC

120K views

Published on: 26/07/2018

How to change serpentine belt on MERCEDES-BENZ A-Class (W169) – replacement guide

Free download PDF
1.38 MB
How to change engine oil and filter on BMW 1 Hatchback (F20) – replacement guide

Free download PDF
1.62 MB
How to change engine thermostat on VW Golf VI Hatchback (5K1) – replacement guide

Free download PDF
4.12 MB
How to change water pump & timing belt kit on Ford Fiesta JA8 – replacement guide

Free download PDF
7.83 MB
How to change front strut mount on AUDI A1 Hatchback (8X1, 8XK) – replacement guide

Free download PDF
3.8 MB
How to change water pump & timing belt kit on Peugeot 307 SW – replacement guide

Free download PDF
7.01 MB

Want to get more useful information?

Ask questions or share your repair experience on the car forum. Subscribe to updates so you don't miss out on new guides.

Ask on the forum

When, why, and how to change engine oil | AUTODOC tips

7K views

Published on: 16/08/2024
How to Fix a Squealing Belt: Causes & Solutions | AUTODOC Expert Tips

5K views

Published on: 04/03/2021
How to unlock your car without a key | AUTODOC tips

2M views

Published on: 15/09/2022
Top Automatic Transmission Blunders You Must Dodge | AUTODOC Insights

7K views

Published on: 26/01/2021