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Discussion Starter #1
Hey guys,

I just went out to run some errands and when I started the STi up, the ABS indicator was lit (and didn't go out) and the DCCD light was flashing on the very bottom circle.

I experienced this once before after I had washed the car and let it sit in the garage over night (it was dried thoroughly though.) Anyhow, I figured that the pads had rusted to the rotors or something to that effect and caused the ABS test to fail. At this time I didn't realize that the flashing DCCD was something different. All I did was turn the car off and roll it out of the garage while applying the brakes. Once on the driveway I pulled the parking brake and just gave a few gentle pumps on the brakes. When I started the car again, the indicators did not show up. Everything seemed fined and the car ran really well.

That was about two to three weeks ago. When I went to run my errand today, the same thing occurred. This time though, rolling the car didn't seem to affect it. As I was backing out of the garage, the rear end seemed weird while turning on the street in reverse. I've haven't played with the DCCD yet so this could be normal when the DCCD is in full-open.

After I pulled back into the driveway to let the car warmup a bit, I figured I'd shut the car off and try again. So when I turned the car back on, the ABS indicator stayed on but the DCCD light went away. Argh! So I shut it off one more time, rolled back a bit, then started her up again. All the indicators shut off this time and the car drove like normal.

I had washed the car two days prior and had it in for its early oil change yesterday. It was driving fine on both days.

The last thing I want to do is have to take my brand new car into the dealer and have them start taking things a part, looking for the problem. Then again, I really do not want my drivetrain to be damaged due to a bad centre diff.

Has anyone experienced this before? Recommendations?
 

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Discussion Starter #2
UPDATE:

The tech at the dealer pulled the ABS code and it came back with one of the G-sensor codes. So they are going to replace the G sensor.

Unfortunately, it is going to take about a week to get the part but the good news is that there is nothing mechanically wrong with the car. They are not sure what caused this problem - probably just a faulty unit. I'm just hoping that is the only problem! :)
 

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Discussion Starter #4 (Edited)
I have this thread going in two different forums (I was desparate for answers :)) so I'll post what I posted on the other forum:

There are apparently two G sensors in the STi. This is according to the 04 service manual. One is called a "lateral G-sensor", while the other is just a "G-sensor". If I were to take a guess, I'd say the "lateral G-sensor" is for detecting cornering-Gs, while the other sensor is for detecting acceleration and deceleration G-forces. The accel/decel G-sensor may aid the ABS system in detecting loads during deceleration. The DCCD probably uses this sensor (among a slew of others, including the lateral sensor) for auto-torque binding as well during hard acceleration and braking, at least when in auto mode. This is just a guess!

So apparently the 04s have two G-sensors: a G-Sensor and Lateral G-Sensor.

The 05s have two sensors as well: a G-Sensor and Yaw-Rate Sensor. Apparently the 05 yaw-rate sensor replaces the lateral G-sensor in the 04.

From what I could tell from the 04's service manual, the DCCD and ABS are both tied into the G-sensors. If one fails, it can cause a failure in both systems.

Here are some pictures I labelled from the "04 vs 05 suspension differences?" thread.





Hopefully, just replacing the G-sensor on my 05 will be sufficient.

Edit: for some reason the img tags are only showing links and not embedding...do I need more posts or something?
 

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Discussion Starter #5
Update #2:

Well I've been having a really fun week with my STi. I had my G-sensor replaced today and took the car out for a 45 minute drive. Just as I was on my way home, the problem occurred again. So apparently, replacing the G-sensor did not fix the problem.

So I brought the car back in immediately, they pulled the codes again and came up with Lateral-G sensor failure (same code.) Apparently though, the yaw-rate sensor houses a 2nd sensor called the lateral-G sensor (saw it in the wiring diagram.) So the dealer pulled a yaw-sensor from one of their new 05 STis and put it in my car.

So, thinking everything is fine I take the car out for another drive. Everything seems fine. After dinner I took the wife out to Home Depot. We get in the car to leave, turn it on, and guess what shows up! @#$)(#*$!!!

So now, I've had both sensors replaced and apparently the problem is more insidious than just a failed part.

For the last week, pretty much anytime I drive the car now, the ABS light comes on and the DCCD light starts flashing. It seems random and just seems to happen out of the blue. I can be driving normally, and it just shows up. It is definitely not a warning indicator failure though because I can feel the DCCD in full-open and the ABS definitely isn't working. There is definitely something wrong electrically.

The problem now is that my car will have to go into the shop for some serious diagnostics. Who knows what the hell is wrong with my brand new car.

To say I'm starting to get frustrated is an understatement. To top everything off, my centre differential sounds/feels like it is grinding when I reverse out of the driveway when this problem occurs. I didn't really notice this before. The DCCD is apparently in full open (the bottom light is flashing) when the ABS failure light comes on and I get a mild grinding and vibration when reversing and turning out of my driveway. Is this normal?

A few things I learned today:

- the yaw-rate sensor incorporates a lateral-G sensor.

- the 04 has 2 G sensors: a lateral-G sensor and a G-sensor

- the 05 has 3 G sensors: a lateral-G sensor + yaw-rate sensor (housed in the same unit) and a G-sensor (same as 04.)

- if your yaw-rate sensor ever goes outside of warranty it will cost $750 CDN to replace.

- the centre console cover is very easy to nick apparently. I now have a few small nicks in my previously pristine console cover from the dealer having to take it off twice now. I was going to let it go, but with all the hassle I've gone through so far, I think I'm going to ask for a new console cover.

- the dealership has been very nice and helpful and has definitely made me feel like they care about resolving this promptly.

Unfortunately, so far I've wasted about 20 hours of vacation time on this problem. I have a feeling it is going to take a LOT more time to fully figure out this problem.

I'm trying to stay positive and relaxed but this problem is starting to get to me. I've owned my car for 1 month and a week and for about a month of that I have been suffering with this problem. I just want to be able to drive my STi without having to worry this problem.
 

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Discussion Starter #6
Forgot to give a final update:

After replacing my G-sensor and Yaw-Rate/Lateral-G sensor (one unit), it turned out to actually be a faulty DCCD control module (it sits behind the glove box.)

Everything appears to be fixed now.
 

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Just to clarify something for you, friend.

The ABS startup test has nothing to do with the rotors being rusty and rolling the car doesn't do dick for it.

If the test fails it's because of a number of possible reasons such as the ABS compressor can't reach it's operating pressure, ABS vavle is stuck open, or and most commonly, there's just not enough brake fluid in the master cylinder to properly operate the brakes AND charge the ABS compressor. So the car decides that the fluid should stay in circulation of the master cylinder and doesn't charge the ABS light.

When your DCCD control unit failed, the computer then became unsure of the torque distribution and wasn't able to make the proper calculations for abs to stop the vehicle in a straight line, so it disables your ABS system for safety.

Moisture, operating temperature, and rust make no difference in the ABS start up test. :wiggles: :wiggles: :wiggles: for this thread, it's very informative. I was informed of the extra yaw sensor in the 05's a while ago as I used to work for Subaru.

The Yaw sensor makes a trendendous difference in the understeer problems the 04's were plagued with. I certainly haven't experienced it. I keep the DCCD on auto unless I need to launch it, then I bring it back a little.

At any rate, it's up there with the Evo's SAYC in complexity save for the STi doesn't use the ABS system as an active torque limiter(The Evo can apply the brake to a single wheel to enhance cornering stability since it can't drive just a single wheel it does the opposite with the brakes).
 

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Discussion Starter #8 (Edited)
Well I figured that the ABS test doesn't fail due to the rotors rusting after washing. That remark was one of those fleeting moments of stupidity and frustration. The last thing you really want to believe is that your brand new $48k cdn car has a defect from the factory. :)

The actual code pointed to a failure of the yaw-rate/lateral-G sensor. Both the ABS DTC and DCCD DTC indicated the same thing. That is why the dealership originally replaced the yaw-rate sensor. The G-sensor was accidently replaced due to the wrong part being ordered. :D

It is amazing how interdependent all the components are. The new DCCD-A module relies on the yaw-rate & lateral-G sensor, the g-sensor, and the ABS control module. It is amazing how much technology goes into these cars.

When your DCCD control unit failed, the computer then became unsure of the torque distribution and wasn't able to make the proper calculations for abs to stop the vehicle in a straight line, so it disables your ABS system for safety.
That is pretty much the conclusion I came to as well after reading through various sections of the 05 service manual numerous times. At first I just had it backwards as I thought the ABS system was failing and that the DCCD system relied on it somehow.

Thanks for the info.
 

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Discussion Starter #10
Vexamus said:
and when you just say G sensor, you mean to say "longitudinal G sensor." :)

Peace, brother.
I do know what the two different sensors are for. :D I only say "G-sensor" because the manual does not refer to it as a longitudinal G sensor (used to detect acceleration / deceleration forces.)

I can't wait to take this puppy to a track and see how she handles!
 

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The Yaw sensor makes a trendendous difference in the understeer problems the 04's were plagued with.
What "plague" are you speaking of?

I'm assuming you are referring to the tendency of the 04 to track towards the outer circumference of an apex on throttle, and towards the inner circumference off throttle? Yeah..this sounds like understeer by definition, but the big difference is there was never any "push" on the front wheels. Just keep your foot in it and it would claw it's way around anyway.

I found this a bit disconcerting at first, but once it was understood, it could be used as an advantage. In other words, I wouldn't say it was plagued with understeer, but rather that the suspension, front diff and DCCD all played a part in sending a bit of an alarming message to the driver, but it was all driver controllable and never resulted in true oversteer (at least not in my experience).

I think the differences between the 04 and 05 were significant in affecting a change in the handling, and really can't be isolated to just the DCCD or G sensors. There were the aluminum lateral links, the change in front diff from the slow acting Suretrac (which IMHO, is the biggest contributor to the outside drift factor) to the much faster LSD, rear crossmember becoming a 3 point unit, and then the tweaks to the shocks/spring to support the wider track/rims.

anyhooo...sorry for the OT.:cool:
 
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