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A story made the rounds earlier this week discussing a Dodge Challenger SRT Hellcat Jailbreak owner’s denied warranty claim. In that case, the cause of the blown motor was in dispute, and ultimately Dodge revealed that a previous engine tune left a permanent record within the engine. However, Dodge dealers aren’t alone know when your car has been tuned. And just like in this case, flashing it back to stock won’t save you.

Volkswagen and Audi dealers can detect tuned cars

These days, more automakers are including technology that records each time the engine management system has been messed with. With most tuning software, tuners are altering the engine’s onboard computer with new parameters that allow for more performance.

Generally speaking, tunes alter fuel delivery, boost pressure, throttle response, and valve timing to bring out the engine’s full potential. For those of us who like performance, these are great options over the more conservative factory settings.

In the case of Volkswagen and Audi though, these tunes will place a permanent TD1 code on the engine’s computer. In essence, this tells any technicians that the car has been tuned, and that may determine the validity of future warranty claims.

Much like in the case of the Dodge from this week, it is up to the manufacturer to decide whether or not to honor the warranty on a tuned car. Some lucky owners have gotten away with warranty claims on tuned cars if Volkswagen believes the issue was inevitable regardless. But in most cases, that TD1 code means you’ll be paying out of pocket for any future engine repairs, regardless of mileage.

Does BMW know if you tune your car?

The E46 BMW M3, like this one in silver, can be tuned to make more power.
E46 BMW M3 CSL | BMW

For BMW, the answer is less clear. While some owners report that BMW techs don’t look for tunes, others say that when looking into warranty claims, the Bavarian brand can detect a tune, even if it has been removed.

Since these cars have consistent data logs for boost pressure, fuel pressure, and more, it is highly likely that a tech would know whether or not the BMW was tuned if brought in for warranty service.

However, BMW offers in-house tuning and M Performance parts to boost performance without voiding the warranty.

What tunes are undetectable?

Whether you have a Dodge, BMW, Volkswagen, or any other car, there are so-called ‘undetectable’ tunes available. These tuning options use a ‘piggyback’ system that alters the signals sent from the engine’s onboard computer.

Rather than changing the OEM software, this setup simply rewrites the signals between the computer and the engine. However, these tunes are riskier, as they aren’t receiving feedback from the engine.

That means they can’t compensate for fuel quality, air density, or temperatures. Instead, they simply send more boost into the engine, regardless of conditions.

Avoid engine damage with a quality tune

Whether your engine is under warranty or not, finding a reputable tuner is always important. It’s also wise to understand the supporting modifications your car needs to handle extra power without worry.

The open world of the internet is a wonderful thing. But when it comes to keeping your car healthy and getting more performance, it pays to have a local tuner that can customize your tune to your specific engine and help make more power with less risk of damage.

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