Will A Tune Void My Warranty?

[Apex Chase]

In “Will This Mod Void My Warranty?” we explored the relationship between modifying your car and warranty law. The conclusion of that post was that a service department or automotive manufacturer can not legally void your warranty simply because you have installed aftermarket parts or have modified your vehicle. They can, however, deny a warranty claim if they can prove the issue in question was a direct result of the installed part or modification. But how does that information apply to those who want or need a performance tune?

The programming in your ECU (Electronic Control Unit) controls every aspect of the engine’s operation: fuel and ignition maps, variable valve timing, rev limits, speed limiters, and many other functions. From the factory a car’s tune is typically set pretty conservatively in an effort to strike a balance between performance, emissions, fuel mileage, and reliability. Air/fuel ratios are generally a little rich and ignition timing is generally retarded to reduce the likelihood of detonation. Rev limits are set low to reduce wear and stress. And on and on it goes. Adjusting many of these setting will result in more power and better performance but, like almost all performance upgrades, it is a give and take. A leaner fuel map and advanced timing will add power but leaves you more vulnerable to detonation. A higher red line allows you to run out a little longer but at the cost of additional wear and an increased risk of a catastrophic failure. An experienced professional tuner is capable of writing a well balanced custom performance tune, but the OEM manufacturers (AKA: the guys who are ultimately on the hook for the warranty) see it differently.

The OEM manufacturer’s stance in almost all cases is that any change to the stock tune exposes the engine and drive train to unknown and untested stresses that can negatively impact reliability. Because of the unknown consequences of this additional stress it is the policy of most OEMs to cancel all remaining engine and drive train warranty. Below are PDF copies of Ford and GM service bulletins laying out their policies on the matter. (I realize this is an FRS/BRZ forum but the company I work for specializes in Camaro and Mustang so I have these bulletins handy. If something similar for Subaru and Toyota comes up I'll add them.)

GM 09-06-04-026A

Ford 11-7-7

If you get a tune and then have an engine or drive train problem you are most likely going to have a serious uphill battle. The thing to keep in mind is that the Magnuson-Moss Warranty Act (15 U.S.C. 2302(C)) still applies. The burden of proof is on the service department and manufacturer to prove the issue in question is the direct result of the tune. If it is not or they can not do that then they have to honor the warranty. If they can you are on the hook.

A tune is absolutely necessary for anyone looking to make significantly more power. My advice is to focus on other aspects of your vehicle until you are prepared to take responsibility if a drivetrain issue were to arise. Once you are, the sky is the limit.

[Thunderchicken]

Originally Posted by Apex Chase

In “Will This Mod Void My Warranty?” we explored the relationship between modifying your car and warranty law. The conclusion of that post was that a service department or automotive manufacturer can not legally void your warranty simply because you have installed aftermarket parts or have modified your vehicle. They can, however, deny a warranty claim if they can prove the issue in question was a direct result of the installed part or modification. But how does that information apply to those who want or need a performance tune?

The programming in your ECU (Electronic Control Unit) controls every aspect of the engine’s operation: fuel and ignition maps, variable valve timing, rev limits, speed limiters, and many other functions. From the factory a car’s tune is typically set pretty conservatively in an effort to strike a balance between performance, emissions, fuel mileage, and reliability. Air/fuel ratios are generally a little rich and ignition timing is generally retarded to reduce the likelihood of detonation. Rev limits are set low to reduce wear and stress. And on and on it goes. Adjusting many of these setting will result in more power and better performance but, like almost all performance upgrades, it is a give and take. A leaner fuel map and advanced timing will add power but leaves you more vulnerable to detonation. A higher red line allows you to run out a little longer but at the cost of additional wear and an increased risk of a catastrophic failure. An experienced professional tuner is capable of writing a well balanced custom performance tune, but the OEM manufacturers (AKA: the guys who are ultimately on the hook for the warranty) see it differently.

The OEM manufacturer’s stance in almost all cases is that any change to the stock tune exposes the engine and drive train to unknown and untested stresses that can negatively impact reliability. Because of the unknown consequences of this additional stress it is the policy of most OEMs to cancel all remaining engine and drive train warranty. Below are PDF copies of Ford and GM service bulletins laying out their policies on the matter. (I realize this is an FRS/BRZ forum but the company I work for specializes in Camaro and Mustang so I have these bulletins handy. If something similar for Subaru and Toyota comes up I'll add them.)

GM 09-06-04-026A

Ford 11-7-7

If you get a tune and then have an engine or drive train problem you are most likely going to have a serious uphill battle. The thing to keep in mind is that the Magnuson-Moss Warranty Act (15 U.S.C. 2302(C)) still applies. The burden of proof is on the service department and manufacturer to prove the issue in question is the direct result of the tune. If it is not or they can not do that then they have to honor the warranty. If they can you are on the hook.

A tune is absolutely necessary for anyone looking to make significantly more power. My advice is to focus on other aspects of your vehicle until you are prepared to take responsibility if a drivetrain issue were to arise. Once you are, the sky is the limit.

I would like to add that the Manufacturer is also on the hook for emission controls set by state and fed. which gives the Manufacturer even more reason not to fix it on their dime.

[Tradewind]

Without reading into this too much I would say if they (dealership) smell a tune when you are trying to claim an engine repair like a holed piston or such ......... you will be on your own for certain

[ed209]

short answer? yes.

[EvoXDD]

Yes ecu flash equals no warranty. Thin again I have about 20k into my Evo x and have tuned and flashed over 100'times easy and mitsu didn't even check

[EvoXDD]

Originally Posted by justaquestion

How do you know they didn't check? Do you stand over their shoulder when they are in the garage?

Modifying a car doesn't equal no warranty. Dealerships have to prove that the aftermarket part/software caused the issue.

You can't even unplug your battery anymore with out the ecu logging it.

Actually yes i did stand there the entire time.

Also the Evo ECU has no flash count, so the helps.

Also in EVERY sports car warranty manual it states (not exact words) any modification to the vehicles computer (or control unit) automatically voids the warranty. I know all about the act that states they have to prove you mod caused the problem, but changing the parameters of a cars ECU can prove to cause any problem they want to prove.

[bet00ST]

Yes ecu flash equals no warranty. Thin again I have about 20k into my Evo x and have tuned and flashed over 100'times easy and mitsu didn't even check

[AJ@ECSMotorsports]

I've seen it go both ways and a majority of the time it depends on the service manager/advisor and your relationship with them.. Often times it is worth driving farther to a better dealership for service with/without mods

[AJUSA.com]

There is a lot of misinformation in this thread. Most of the time the dealer cannot tell a flash was added unless the aftermarket tune is still loaded. They can tell the ECU was accessed as a log would be present, but leaving your lights on and letting the battery die would leave the same type of impression on the ECU.

Be careful, know your car & how aftermarket products interface with it, research everything & you should be just fine.

[Jordo!]

If detected, and you roast a motor, yes.

[Ft86Chris]

On this note, I have a tune, But am throwing a Coil pack issue, with 20,000kms on the car ( code; P0351 ) Haven't mentioned my tune, but I don't believe my tune could effect the coil packs, but than again I could be wrong

[Kodename47]

The coil pack operation isn't going to be affected by a tune therefore it is defective hardware that should be covered. However it seems that you Americans tend to get a raw deal.

Known issues like AVCS and coil packs etc should always be covered no matter what. It is the way here in the UK anyway. I know a turbo car that had numerous AVCS fixed tried under Subaru warranty.