Sojo40

Looking for some sound opinions,
I was driving a 04 cl600 yesterday of a friends that he thinks has the starting of an accumulater issue. He drove up to my house came in for a minute then we left, the car was just a tad low up, front but never completely drops. As I Starting going and I could feel it move up in height just a bit as I put it in drive.
We got on the freeway and after about 10 mins I felt the cars body move down toward to left as I turned a bit left then I turned it to the right immediately and it moved down on the right. It was like it was having an issue auto leveling. Then as I turned left to see what the heck was happening it wildly dropped over left and I turned it right and it dropped wildly right, oh and as it did that the other side would go up to normal. When it would drop on the left the right was normal then turn it a bit right it would drop and left would be normal. I pulled to the side of the road and popped the hood to check for leaks or what not, and hit the abc button to check that and it did fine.. I did it several times and it hasn't done it again so far.
My thinking is that the auto leveling accumulater is failing and it caused a vacuum pocket so it dropped once it got to the pump or the pump is starting to have issues maintaining pressure meaning it's going out.
If anyone knows about this please share any info.
I would hate to see my bud crash that sweet ride.
Thanks all.

graytalon2000

I had something similar happen to my ride. It would suddenly drop on one side or one corner for no apparent reason then just as suddenly rebound to normal. At first, I thought is was a glitch since there were no warning messages or lights but, it progressively got worse so, I quit driving it and did some research. I came across a TSB that described a very similar issue with older CL's, I think it is the 00-02 models that stated the acceleration sensors on the strut towers could be bad due to faulty soldering. Mine is an 05 so I figured the sensors were not the cause since they were the "updated" versions. Anyway, I decided to try used replacements since I had no other ideas and low and behold, they cured the problem. NOTE - the 2 sensors on the strut towers are vertical sensors and there is supposed to be another one near the center console that is a lateral sensor although, I never laid eyes on that one. I only changed the ones on the strut towers. I'm not saying this will cure your issue but it worked on mine. I never had mine scanned for faults so, there could have been codes set. You may want to go that route first.

biker349

good info. thanks it would be interseting to see what a star scan shows.

tusabes

Accumulators would not cause the issue . All they are are spheres filled with inert nitrogen gas inside a rubber bladder to help smooth the ride, they do not control lifting or lowering

Sojo40

Yeah that was just a thought I figured it is more likely the pump, but is it possible for the ride level accumulator to have ruptured as we were driving because it was a rough patch of road from construction we were riding on when it happened at 65+ mph, my thought that maybe the diaphragm ruptured which caused the fluid to fill up the whole sphere which caused a pressure change in the system which at 3000psi a little change could cause a difference in the struts, that could have caused an uneven pressure rate in the strut making the auto level sensors to react a bit aggressive. (All a theory but plausible?) Or It could be the auto level sensors them self just seems weird if it is the sensors that both would act up at the same time, I guess he needs to have it scanned.
Thanks for the replies I can always count on great responses from my fellow forums friends.

tusabes

If an accumlator blew it could cause a sudden change when it fills up, but you've described this as a recurring problem

It's also likely not a pump issue

My bet is bad sensors or valve block problem . Sticky valves often cause lifts and drops

Sojo40

That the thing it only did it that one time, we tried to dulicate the issue but hasn't done it again.
If the accumulator blew wouldn't the ride be rough or stiff? It still rides nice and smooth.
I had my fair issues with abc so I know there is no such thing as just a one time anomaly, it will maybe give you a lil tap on the door that a problem is coming then it just busts the door down and craps on your new carpet...lol

tusabes

Again if it was just a one time thing that points to a sticky valve in the valve block or an intermittent sensor fault

A ruptured accumlator or bad pump would be noticed all the time

awiner

As GrayTalon pointed out this is common when Acceleration Sensors start to fail. It will happen sporadically. Sometimes months apart. When it happens it can be very violent and pitch the car into another lane if not caught fast enough. Also can cause a sudden drop in height that may rub the tires inside the wheel wells causing noise and scaring the crap out of you.

There are three vertical sensors. One on each strut tower and one inside the rear cabin, under the rear paneling near the right side strut if I remember correctly.

STAR won't show faults when these start to go bad.

Sojo40

Woohoa, that is a lil disconcerting to say the least. With all the sensors for sensors how would it not trigger a fault code of some sort? So just replace all the sensors related, or just the acceleration sensors?
I find it crazy that as sophisticated and deep the STAR diag.can dig into the systems and sensors that it can't find out which sensors would be bad, or code triggered.
Thanks for this info.
Does anyone have a good diagram for what sensors is what and the location of each and the part number. I guess replacing all the sensors is the only thing we can do.
Since I will be helping my buddy do this any help with the diagram and part numbers would be very much appreciated.
As always thanks to all for your helpful replies.

awiner

I would start by simply replacing the two front sensors next to each front strut tower. They are easy to replace (will take you all of 3 minutes max). I honesty believe this will solve your issue. I have NEVER seen a rear sensor go out. I think the fronts tend to go out because of the heat/cool cycles they experience being in the engine compartment.

The sensors are just sending erroneous data to the ABC control module which then reacts. The system doesn't realize this is a fault and therefore there is no error code to store.

The part # of the sensor is A0045423518 -- Available for $40ish a sensor (new).

The body acceleration sensors consist of an electronic vibration module (operating principle spring/mass system). They record the vertical body accelerations and supply signals to the control module.

As stated, there is one on each side of the engine compartment right next to the strut towers. They are little black boxes that are about the size of a match box with a wire running to them. Unplug the connector, remove the screws and reinstall in reverse.

They look like this:



For information, the recalled sensors from the early 2000's had the following "week" codes.

The recalled sensors will have one of the following week codes:

06 W 20
06 W 21
06 W 22
06 W 23
06 W 24
06 W 42

biker349

great info as usual. thanks.