Converting back the Z55 Air Ride Suspension

[Joseph Garcia]

I have a question for you folks who have the Z55 suspension and have recorded Tech 2 snapshot data regarding its functions. Specifically, the Damper Actuator Commands for each of the 4 electric shocks, and their % range of dampening while driving.

I am learning more about my Tech 2, and I practiced by monitoring the function of the electric Damper Actuators in all 4 shocks in real time while driving, and what I noticed is that they all stay on 0% pretty much all of the time. The only time that they consistently move above 0%, is when I brake to a stop, with my foot staying on the brake pedal, such as at a stop light. Then, all 4 Damper Actuators show 20%, until I release the brake and start to move forward. Then, all 4 Damper Actuators revert to 0%. Occasionally, I see one or more of the Damper Actuators go to 20%, but never above that. I have no DTC codes related to the suspension.

So, today, I tried out the Tech 2 Snapshot recording and playback process, figuring that the Damper Actuators may be operating between 0% and 95%, but the changes may be occurring too fast for me to see them in real time on the Tech 2, since the actuators can respond to changes within 20 milliseconds. So, I recorded all 4 of the Damper Actuators (3 at a time), and I drove over a dirt road, complete with potholes, rippled bumps and washouts, and tight curves, just to be sure that the electric suspension would have many changes to respond to. When I reviewed the snapshot recordings plots on my Tech 2, the behavior was the same as my real time observations. ==>> The Damper Actuators typically stayed at 0% and occasionally went up to 20% (typically all 4 Damper Actuators changing in unison), but no higher than 20%, even though the Tech 2's vertical axis on the plot showed a potential Damper Actuator range of 5% to 95%.

I not believe that this is expected behavior for the Z55 suspension electric Damper Actuators, but I'd like to hear from you who have the Z55 suspension, and who have observed their operation with the Tech 2 or a similar scanning/programming tool. All of the suspension components are either brand new, or operating within spec, as observed on the Tech 2. The only 2 significant suspension components that have not been replaced are the suspension control module (15095254) and the yaw rate sensor (25930324).

Please give me your thoughts.

 

[George B]

@swathdiver
James, have you logged the damper actuation?

If I get a chance I will take Heidi out with me to see what mine does tonight.

 

[TollKeeper]

This is one I cant help you with. I got snap shot data of staying static.. Esky is leaving my possession tonight, so...

 

[gooffeyguy]

@swathdiver
James, have you logged the damper actuation?

If I get a chance I will take Heidi out with me to see what mine does tonight.

I don't think he has the Z55 suspension

 

[George B]

I don't think he has the Z55 suspension

Oh, yeah… That’s right.

 

[George B]

Here is a log I took this evening. I graphed it for easier viewing. Pretty cool how mine works.

 

[swathdiver]

Here is a log I took this evening. I graphed it for easier viewing. Pretty cool how mine works.

Really cool! Never seen that as mine has a dumb suspension!

 

[Joseph Garcia]

Here is a log I took this evening. I graphed it for easier viewing. Pretty cool how mine works.

Thank you so much, George, for taking the interest and time to record this data from your truck's Z55 suspension for me. VERY much appreciated.

Again, this Forum and its members ROCK!!

That is what I expected to see in damper behavior on my newly installed Z55 suspension components. Yet, I never saw any of the tall spikes that you show on your recording. I have a few questions for you:

1). What is the vertical scale in your plot? 0%-95%

2). What is the level of most of the low 'square wave' spikes? ~20%?

My question to all of you is what would you recommend that I do next in my attempt to get my Z55 suspension to behave as designed? Given my plot results, where all 4 Damper Actuators are in fact responding, but not more than 20%, (appears not to be a damper function issue nor an electrical wiring issue) should I consider replacing my suspension control module (15095254) as the next step?

I will record additional Damper Actuator data in Tow/Haul Mode, just to see if the responses are different than what I see in normal mode.

Please give me your thoughts.

 

[George B]

Thank you so much, George, for taking the interest and time time to record this data from your truck's Z55 suspension for me. VERY much appreciated.

Again, this Forum and its members ROCK!!

That is what I expected to see in damper behavior on my newly installed Z55 suspension components. Yet, I never saw any of the tall spikes that you show on your recording. I have a few questions for you:

1). What is the vertical scale in your plot? 0%-95%

2). What is the level of most of the low 'square wave' spikes? ~20%?

My question to all of you is what would you recommend that I do next in my attempt to get my Z55 suspension to behave as designed? Given my plot results, where all 4 Damper Actuators are in fact responding, but not more than 20%, (appears not to be a damper function issue nor an electrical wiring issue) should I consider replacing my suspension control module (15095254) as the next step?

I will record additional Damper Actuator data in Tow/Haul Mode, just to see if the responses are different than what I see in normal mode.

Please give me your thoughts.

I am unsure of the scale however as Heidi called out numbers during the logging process the highest I recall was 95% and the square wave spikes are 20%. If you watch on a pc in full screen mode you can see the values displayed in the upper left. Go to 0:50 of the video and go full screen. Looks like the upper scale is 100%

 

[George B]

Also, it took quite a jolt to get the 94% spikes in normal mode.