VW, Audi, SEAT & Škoda Airbag Module No Communication Fault
A common fault affecting selected VAG SRS/airbag control modules can result in complete loss of communication with the module.
This fault can affect vehicles across the Volkswagen Group, including Volkswagen, Audi, SEAT and Škoda, and is commonly associated with selected modules from the 5Q0959655 family.
Typical symptoms include an illuminated airbag warning light, diagnostic equipment being unable to communicate with the SRS module and other control modules reporting that communication with the airbag module has been lost.
At VSR, we offer specialist electronic repair for selected VAG SRS modules suffering from this no-communication fault.
This guide explains the symptoms, how to carry out some initial diagnostic checks and how to determine whether the SRS module itself may be responsible.
What Does "No Communication With SRS Module" Mean?
The SRS (Supplemental Restraint System) module, commonly referred to as the airbag control module, is responsible for monitoring and controlling important parts of the vehicle's restraint system.
It also communicates with other electronic control modules around the vehicle.
When diagnostic equipment reports no communication with the airbag/SRS module, it means communication with the control unit cannot be established.
However, this does not automatically mean the SRS module itself is faulty.
A loss of communication can potentially be caused by:
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Loss of power to the module
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Poor or missing ground
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Wiring damage
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Connector problems
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CAN bus/network faults
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Internal electronic failure within the SRS module
For this reason, some basic diagnostic checks should be carried out before condemning the module.
Common Symptoms of a Failed VAG SRS Module
A VAG SRS module affected by this fault may produce one or more of the following symptoms:
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Airbag/SRS warning light illuminated
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No communication with the airbag module using diagnostic equipment
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SRS module missing from a complete vehicle scan
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Other modules reporting lost communication with the airbag control module
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Airbag-related communication fault codes
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Fuel cut-off related errors
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Multiple communication faults relating to the restraint system
The exact symptoms and fault codes can vary depending on the vehicle.
How to Test for a VAG SRS Module No Communication Fault
Before removing or replacing the SRS module, we recommend carrying out some basic diagnostic checks.
The aim is to establish whether the module has the electrical supplies and communication connections it requires to operate.
Step 1 — Carry Out a Complete Vehicle Scan
Start by performing a complete diagnostic scan of the vehicle.
Check whether the SRS/airbag module is the only control module that cannot be accessed.
If several unrelated control modules are also unavailable, this may indicate a wider vehicle electrical or CAN network problem.
If the rest of the vehicle communicates normally but the diagnostic equipment cannot establish communication with the SRS module, continue with the following checks.
Step 2 — Check Power and Ground at the SRS Module
For the applicable modules covered by this repair, the connections used for the initial checks are:
| Pin | Function |
|---|---|
| 61 | +12V Supply |
| 63 | Ground |
| 89 | CAN High |
| 90 | CAN Low |
Pin 61 — +12V Supply
Check for the correct battery supply at Pin 61.
If the required supply voltage is missing, the module may be unable to power up and communication will not be possible.
A missing supply should therefore be investigated on the vehicle before assuming the SRS module has failed.
Pin 63 — Ground
Check the ground connection at Pin 63.
A poor or missing ground can prevent the module from operating correctly even if +12V is present.
The ground circuit should be checked for integrity rather than relying solely on a simple voltage measurement.
Step 3 — Check CAN High and CAN Low
The SRS module communicates with the vehicle through the CAN network.
For the applicable modules:
Pin 89 — CAN High
Pin 90 — CAN Low
Check that both CAN connections are present and that there is no obvious open circuit, short to ground, short to supply or other wiring problem.
If you have the appropriate diagnostic equipment, the CAN network should be assessed to confirm that the vehicle-side communication circuit is operating correctly.
Step 4 — Assess the Results
If you have established that:
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The rest of the vehicle communicates correctly
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+12V is present at Pin 61
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Ground is satisfactory at Pin 63
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CAN High is connected correctly at Pin 89
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CAN Low is connected correctly at Pin 90
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There are no obvious vehicle-side wiring or network faults
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The SRS module still cannot be accessed with diagnostic equipment
then an you have an internal electronic fault within the SRS module.
Important Diagnostic Note
Correct power and ground readings alone do not prove that an SRS module is faulty.
CAN communication faults can sometimes be caused by wiring problems elsewhere on the network, and other vehicle faults can produce similar symptoms.
For this reason, the complete diagnostic picture should always be considered.
If you're unsure whether your module is actually faulty, VSR can test the module for you before proceeding with a full repair.
VAG 5Q0959655 SRS Module
This no-communication fault is found on selected SRS modules within the 5Q0959655 family used across Volkswagen Group vehicles.
There are numerous hardware and software versions within this family, so checking the complete part number on the module label is important.
Part Numbers Currently Covered by VSR
Our current no-communication repair service covers the following:
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5Q0959655A
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5Q0959655B
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5Q0959655D
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5Q0959655J
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5Q0959655K
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5Q0959655L
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5Q0959655M
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5Q0959655N
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5Q0959655P
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5Q0959655R
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5Q0959655S
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5Q0959655T
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5Q0959655AA
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5Q0959655AB
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5Q0959655AC
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5Q0959655AE
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5Q0959655AJ
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5Q0959655AK
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5Q0959655AM
If your part number isn't listed, please contact VSR before purchasing the repair service.
Sending us a clear photograph of the module label is usually the easiest way for us to check your particular unit.
Can a VAG SRS Module With No Communication Be Repaired?
In most cases, yes.
Once vehicle-side power, ground, wiring and communication problems have been ruled out, the SRS module can be tested to determine whether an internal electronic fault is preventing it from operating correctly.
Rather than automatically replacing the complete unit, VSR carries out component-level electronic repairs where appropriate.
This allows the original module to be retained.
Why Repair the Original SRS Module?
There are several advantages to repairing the original unit rather than immediately replacing it.
Keep the Original Module
The module being repaired is the original unit from your vehicle.
Avoid Finding a Compatible Replacement
Replacement SRS modules can have different part numbers, hardware versions, software versions and vehicle configurations.
Retain the Original Data
Where the original module is successfully repaired for the no-communication fault, its original programming and configuration can be retained therefore the need for coding is removed.
Potentially Reduce Repair Costs
Repairing the electronic fault is considerably more economical than replacing the complete module.
How Does VSR Repair the Module?
Once the module arrives with us, we first assess the unit and confirm the reported fault.
The module's electronic circuitry can then be inspected and tested to identify the cause of the failure.
Where the fault is within the scope of our service, the appropriate component-level electronic repair is carried out.
After repair, the module is tested using our available bench-testing procedures before being returned to the customer.
Does the Module Need Coding After Repair?
When your original module is successfully repaired for this electronic no-communication fault, the existing programming and vehicle configuration are retained.
This means the module does not require any coding after the succesfull repair.
What If I'm Not Sure My Module Is Faulty?
If you have a VAG SRS module with no communication but aren't confident that the module itself is responsible, you don't have to purchase the complete repair immediately.
VSR offers a module diagnostic/test service.
You can send the module to us and we can assess whether the unit itself is operating and communicating correctly.
This can be particularly useful where vehicle-side diagnosis has been inconclusive.
No Communication vs Crash Data
It's important to distinguish between these two services.
A no-communication repair is intended for a module that cannot be accessed normally with diagnostic equipment due to an electronic fault.
A module requiring crash data reset is a different type of service.
If your module communicates normally but has stored crash data following an accident, please select the appropriate crash data service or contact us for advice.
UK-Wide VAG SRS Module Repair
VSR provides a UK-wide postal repair service, so you don't need to bring the complete vehicle to us.
Once you've established that the SRS module may be responsible for the fault:
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Check that your part number is covered.
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Purchase the appropriate VSR repair service.
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Remove and securely package your original module.
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Send the module to VSR.
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We inspect, repair and test it.
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Your original repaired module is returned to you.
Ready to have your module repaired?
[VIEW VAG SRS NO COMMUNICATION REPAIR SERVICE →]
Not sure whether your module is faulty?
[VIEW MODULE DIAGNOSTIC / TEST SERVICE →]