[dttruax]

I think what they meant was that with most newer cars (like 2000 and newer) you can't reset the ecu by just disconnecting the battery but have to hook up a reader or take it to the dealer to have them reset it. I don't know if they're talking about error codes and turning off the check engine light, etc. or just resetting it enough to allow it to "re-learn".

I kind of agree because of past experience. I had a 1998 Dodge Neon and had something happen where the check engine light came on. To reset it, all you had to do was disconnect the battery for a little bit. My dad went and bought a 200 Neon and had the check engine light come on because he didn't tighten the gas cap good enough and tried to reset it by just disconnecting the battery and it didn't work. He had to take it to the dealer and pay to have it reset. The dealer said that with the newer cars, you have to take it to the dealer to get the ecu reset and can no longer do it by just disconnecting the battery.

Is this the same situation with the WRX's (I have a 2004)? Never had the check engine light come on so I don't know. I have had a few times where I had the battery disconnected for a time (recently while changing the spark plugs) and noticed that it drove a lot better afterwords, but thought that was just because of the new plugs.

 

[EJ257]

I have read far more times that if you not only disconnect the bat. but drain the reserve power by pushing the brakes it will reset as opposed to this one post you link.

This will work, and will erase all the "learned" values in the fuel trims, timing, etc. as well as clear any CEL.

 

[Donkey]

People also need to understand the check engine light isn't going to magically go away unless the issue is resolved as well.

 

[8007]

I am sorry but I have no idea what "non-volatile" means technically in this context. I have read far more times that if you not only disconnect the bat. but drain the reserve power by pushing the brakes it will reset as opposed to this one post you link. However, this is some seriously old school thread and I have personally only used an AP or a cable and romraider myself. I didn't reread the thread but I am guessing they are talking about riding your brakes to get your IAM up after a reflash. Don't do that. You can set where your map resets to in the editor.

This is assuming you have an editor though. If not, the brake torque method does work...for a short duration. I proved it to myself at the strip. I wouldn't do this on a hot day though.

 

[Donkey]

You can also just run do a couple of quick WOT runs and the IAM should come up(if nothings wrong). You really don't have to do the "Vishnu trick".

 

[kbrok]

if you have a utec with tunes on it and you reset the ecu. it will load the tunes again and adjust for the remainder correct

 

[crue313]

Will resetting the ecu clear CELs?

 

[freezed0wn]

To clarify, since this is a pretty old thread:

An ECU reset does not require a time period to wait after the battery is disconnected. Just disconnect it, tap the brake pedal, and reconnect it. You are done.

For maximum affect, after resetting, get on a open surface with no traffic, place the car in 3rd gear, increase throttle, and slowly let up on the clutch while brake torquing the car (don't let it move). The object is to increase boost for a time frame of around 5 seconds. This will maximise your ECU settings such that you will immediately gain a good 20 HP over the "worn" stock ECU settings. The background is much more complex than this, but this does work.

Uh, won't this burn up the clutch?

 

[paascal]

To clarify, since this is a pretty old thread:

An ECU reset does not require a time period to wait after the battery is disconnected. Just disconnect it, tap the brake pedal, and reconnect it. You are done.

For maximum affect, after resetting, get on a open surface with no traffic, place the car in 3rd gear, increase throttle, and slowly let up on the clutch while brake torquing the car (don't let it move). The object is to increase boost for a time frame of around 5 seconds. This will maximise your ECU settings such that you will immediately gain a good 20 HP over the "worn" stock ECU settings. The background is much more complex than this, but this does work.

has this ever been documented on a dyno?

 

[Fast4Door]

My name is Austin and I just bought a 2004 wrx with 90k on the motor and the guy that I bought it from modded the car with 1000cc injectors, a 20g turbo, a full exhaust system, and a perrin intake. I want to return the car back to stock and I have most of the parts to get the thing back to stock but the guy put a base tune on the car, meaning that the car is not tuned for the parts and runs like garbage. I was just wondering how to get a stock tune either with a access port, get it pro tuned back to stock or do a ecu swap if that could work. I want to get my car back on the road so I can drive it.

Please Help!

 

[219673]

Put the stock parts on, tow it to a performance shop and have them tune it

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[mycologist]

If it has an accessport installed you can use that to revert it to stock. If it isn't already installed it isn't worth it but you should be able to get a stock map to load.

You can use an openport cable and ECUFlash for much less than an accessport. It shouldn't be hard to find a stock '04 map online. The instructions for reflashing are in the tuning section stickies.

 

[Zacdak 1971]

I just bought a 2016 WRX. I live in a state where I have to pass an emissions test. My car keeps rejecting so I took it to Subaru. They can't find anything wrong with it. There are no alerts and they have done the drive cycle and they can not get the computer to reset. They are supposed to call the factory because they think it's a computer glitch but I haven't heard back from them yet. Has anyone else experienced this????

 

[03BlobWagWrx]

Sorry for reviving such an old thread but my WRX has been running a bit rough since I changed the cam/crank/temp sensors and I've just tried this and it seems like a new car again!
I also did the rolling 3rd gear accel/brake thing for first boost after reset. Not sure if that itself made a big difference but the car definitely seems to be running better.

Thanks to all of you that input in to this thread

 

[Delphince]

For anyone reading this, do NOT follow this advise. Prolonged (such as 5 seconds) light contact between a clutch and flywheel at RPMs that will produce boost will glaze your clutch pad and put hot spots in your flywheel. While they perform similar functions, clutch and brake pad materials are not the same, and do not tolerate slippage in the same way.

 

[Delphince]

Ditto what was said earlier. The object is to maintain a mid to high steady level of boost for a duration which really can't be achieved unless you are in 5th (or 6th for the STi) and at high rate of speed....and even here the boost is still climbing, which will have an impact on the ecu reset rate.

In short, if you do it right, there is not threat at all to the clutch. In 3rd, it doesn't really put a lot of torque on the drivetrain, but it is low enough for the ECU to quickly allow some boost.

For those with some minor mods...exhaust, etc....you won't believe the difference this makes. It really is noticable.

For anyone reading this, do NOT follow this advise. Prolonged (such as 5 seconds) light contact between a clutch and flywheel at RPMs that will produce boost will glaze your clutch pad and put hot spots in your flywheel. While they perform similar functions, clutch and brake pad materials are not the same, and do not tolerate slippage in the same way.

 

[Delphince]

To clarify, since this is a pretty old thread:

An ECU reset does not require a time period to wait after the battery is disconnected. Just disconnect it, tap the brake pedal, and reconnect it. You are done.

For maximum affect, after resetting, get on a open surface with no traffic, place the car in 3rd gear, increase throttle, and slowly let up on the clutch while brake torquing the car (don't let it move). The object is to increase boost for a time frame of around 5 seconds. This will maximise your ECU settings such that you will immediately gain a good 20 HP over the "worn" stock ECU settings. The background is much more complex than this, but this does work.

For anyone reading this, do NOT follow this advise. Prolonged (such as 5 seconds) light contact between a clutch and flywheel at RPMs that will produce high boost will glaze your clutch pad and put hot spots in your flywheel. While they perform similar functions, clutch and brake pad materials are not the same, and do not tolerate slippage in the same way.

 

[Delphince]

I'm thinking this is getting a bit more complicated that it is. It's simple. Turn car on. Put clutch in. Set E-brake full on. Place in 3rd. Give throttle. Slowly let up on clutch while giving throttle to keep RPMS above 3K/positive boost pressure. Keep clutch slightly out and throttle slightly in for ~ 5 seconds. Done.

There is likely less abuse to the clutch than a normal spirited takeoff. It's over before you know it. Yes, you can also brake torque it while moving, but for me, there is now a safety risk to others when focusing on doing this rather than driving. I'd rather keep it safe and simple right in my own driveway.👍

For anyone reading this, do NOT follow this advise. Prolonged (such as 5 seconds) light contact between a clutch and flywheel at RPMs that will produce high boost will glaze your clutch pad and put hot spots in your flywheel. While they perform similar functions, clutch and brake pad materials are not the same, and do not tolerate slippage in the same way.

 

[zax]

For anyone reading this, do NOT follow this advise. Prolonged (such as 5 seconds) light contact between a clutch and flywheel at RPMs that will produce high boost will glaze your clutch pad and put hot spots in your flywheel. While they perform similar functions, clutch and brake pad materials are not the same, and do not tolerate slippage in the same way.

That post was irony…