U0495: Invalid Data Received From Digital Audio Control Module B
What to do
The car drives normally. This is a second sound processor, on a system big enough to have been split into two.
There is a free test worth doing, and it will genuinely narrow things down. Is the sound wrong everywhere, or only at one end of the car? If the front speakers sound wrong and the rear are fine — or the other way round — that confirms it is one of the processors rather than the stereo itself, because a fault in the stereo would affect all of it.
If both ends sound wrong, the problem is more likely to be something feeding both processors than both of them failing at once, and there is no point in replacing either.
Everything at U0494 applies here too — including the point worth repeating: if the car has started making a new droning or booming noise, or the engine suddenly sounds different, that may be this fault rather than the exhaust or the suspension. Say so before anything is dismantled.
What this code means
A second digital audio control module is broadcasting data that cannot be accepted as true. See U0494 for what these modules do, including the two jobs that have nothing to do with music.
A second processor means a system large enough to have been divided — a premium branded audio installation with front and rear processing, a separate unit for the rear cabin, or on a long vehicle a processor at each end so that the signal does not have to travel the length of the car in analogue form.
Which gives a useful test where both exist: does the fault follow the zone? Sound wrong at the front but right at the rear, or vice versa, confirms which processor is involved and rules out the head unit and the source — because a fault in either of those would affect everything. That costs nothing and settles the question before anyone starts removing trim.
And where both processors report at once, look past them both, exactly as at U0454: two independent units failing together is far less likely than one thing feeding both — the head unit, a shared supply, or the network itself.
Otherwise everything at U0494 applies, including the noise cancellation and synthesised engine sound arguments and the warning about aftermarket head units.
Likely causes
Start here
- Corroded or loose connector · easy
- Aftermarket head unit fitted in place of the original · moderate
- Module not coded to the vehicle · specialist
Less common
- Water ingress into module · moderate
- Damaged data bus wiring · moderate
- Damaged wiring harness · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
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