Meaning of TCCMODE

[LS1_Dragster]

What does the following commands mean exactly:

TCCMODE PID

AppEn = ?
App = ?

I'm getting real harsh shifts on the 1-2 so I logged TCCMODE and 'AppEn' is on just prior to the 1-2 shift and stays on through the 2-3 shift then goes to 'App' then to 'lock'.

What exactly is being commanded when it's stating 'AppEn'.

'App' obviously is in the apply stage and then goes into the locked stage but I don't know what 'AppEn' is accomplishing.

I'm starting to think the converter is locking during 2nd gear, either by a command or a hardware failure.

[mr.prick]

Status parameter {GM.TCCMODE}
TCC Mode
(Enumerated PID)
Value Caption Description
0 Off TCC Off
1 Rel TCC Releasing
2 App TCC Applying
3 AppEn TCC Apply Enabled
4 Lock TCC Locked
5 Coast TCC Coast
6 Slew TCC Slewed

Right click the PID for more info.
Unfortunately not all PIDs offer "more info" :bad:

[LS1_Dragster]

Thanks, but you just stated the obvious! I can and did read that but I'm after the meaning and what exactly is it doing compared to just the App.

Why does it have AppEn from the 1-2 shift, through 2nd past the 2-3 shift then it goes to App then lock, is it actually doing anything to the trans during that stage or is it just there and not doing anything?

Lee

[joecar]

Apply Enable is where the TCC pressure ramped up (via TCC PWM) part way, but not all the way to Locked;

Apply Enable seems to occur between Off and Applying, and sometimes appears to be optional;

The sequence seems to be either of:
Off->Apply Enable->Applying->Locked
Off->Applying->Locked

Applying does not take the TCC all the way to Locked;

Slew or Slewing may be the ramping up/down of TCC pressure over time (but not during Locked);

Coast or Coasting may be where the TCC is unlocked (different than Releasing) and the pressure ramped down part way, but not all the way to Off;

Releasing takes the TCC all the way to Off;


The GM Service Manuals and Hydra-Matic Technician Guides don't refer to those states at all... showpost.php?p=39479&postcount=5 (http://forum.efilive.com/showpost.php?p=39479&postcount=5)

Log TCCMODE, TCCDC, TSTATE00, 03, 09, 10, 12 to get a clearer idea of what the PCM is doing...

For the TCC to be locked, the TCC Enable solenoid has to be on and the TCC PWM solenoid has to be above 95%.

Apply Enable may mean that the TCC Enable solenoid is on and the TCC PWM solenoid is somewhere between 10% and 90%.


Edit: corrections after reviewing my old logs.

[LS1_Dragster]

Mines a little different.

Mine goes AppEn then App then Lock.

If I understand this correctly, the system prepares itself to apply fluid once 2nd gear is enabled (AppEn) now the TCC solenoid is bleeding off this pressure but once the TCC solenoid is energized it no longer bleeds of this pressure (App) then shortly after it's now locked under full pressure.

Is it possible to have the fluid from the AppEn actually start to engage the lockup IF the TCC solenoid is partially failed or stuck in a way so it lets it build pressure to engage the clutch but still not trip a code?

Attached is a screen shot of just normal driving, you can see the VSS jump at the 1-2 shift because it barks the tires, this is even more evident at WOT. Also notice how it pulls timing big time in 2nd gear until it shifts into 3rd. I have no idea where it's getting this timing figure from because I changed the timing in the 'engine protection mode' B5912 to 26 degrees.

Also notice how the TCCSLIP ramps down from dead stop and keeps ramping down even during the 1-2 and 2-3 shifts. This appears to be odd since I have a 2500RPM stall converter, the slip should increase or ramp up after each gear change but less RPM's then the shift before (trans speed is catching up to the engine speed)

Now look at the screen shot from my firebird and watch how the TCCSLIP ramps down from a start but ramps back up after each shift, this to me is exactly how my Yukon should look but with less slip since the firebirds converter is a 3500 stall.

I think I have a defective or clogged TCC solenoid.....

Lee

[LS1_Dragster]

BTW, I only have TSTATE00, 01, 33-37, 39-40, 42 and 45

[joecar]

BTW, I dont see TSTATE09, 10 or 12, I do have TSTATE00 thru 08 also 33-37, 39-40, 42 and 45You mean in V2 BBL...?

I notified Paul regarding that (those pids either will not display in the scantool since the scantool has no interpretation for TSTATE 33-45).

You would have to log those using the scantool/laptop until they are fixed in BBL.

[LS1_Dragster]

correct, I will have to drag the laptop with the next run then.

[joecar]

Mines a little different.

Mine goes AppEn then App then Lock.
...

Yeah, you're right, I looked at my old logs and edited (blue ink) post #4 accordingly...

[joecar]

Your Firebird log shows the TC allowing the engine rpm to "extend" rather than drop down on take up of shifted gear.

Also note that AppEn means that the TCC may be being partially applied (to control the TCC apply "feel")... see attached diagram and see this description: showpost.php?p=39479&postcount=5 (http://forum.efilive.com/showpost.php?p=39479&postcount=5)

[joecar]

You mean in V2 BBL...?

I notified Paul regarding that (those pids either will not display in the scantool since the scantool has no interpretation for TSTATE 33-45).

You would have to log those using the scantool/laptop until they are fixed in BBL.I heard back from Paul, he said he added code to the scantool to translate the TSTATE pid names...

He had to rename the BBL TSTATE pid names to maintain compatibility between vehicle platforms.

[LS1_Dragster]

OK, did another test drive.

Look at frame 3100, There are a couple of issues:

1) Real hard 1-2 shift, 6000 pound 4x4 now stock with 38" tires and it spins 6MPH at the shift, something will break in the trans soon....

2) The timing takes a dive on the 1-2 and stays there for 2/3 of the run then goes back to normal, you can hear and feel the truck pickup and start moving.

3) The AFR takes a dive and goes rich

4) The converter slip RPM goes from 235RPM to a negative -587RPM during this flat spot

5) The trans pressure stays at 79psi during the flat spot then lowers to 50psi when it picks back up

6) The converter rebounds from a -587 to 423RPM when it picks back up.

I'm thinking that when the computer commands the 'AppEn' or when the pressure is over 50psi the converter is locking by itself -OR- somehow it's going into some failsafe mode by pulling timing, adding fuel and locking the converter. Is there any PID's that I can log that would let me in on what the computer is thinking?

[joecar]

In that log follow fromthe [Data] tab:
TSTATE00-TCCESOL
TSTATE12-TCCEN
TSTATE12-TCCMAXP
TCCDC
TCCMODE

[MyM8V8]

Apply Enable is where the TCC pressure ramped up (via TCC PWM) part way, but not all the way to Locked;

Apply Enable seems to occur between Off and Applying, and sometimes appears to be optional;

The sequence seems to be either of:
Off->Apply Enable->Applying->Locked
Off->Applying->Locked

Applying does not take the TCC all the way to Locked;

Slew or Slewing may be the ramping up/down of TCC pressure over time (but not during Locked);

Coast or Coasting may be where the TCC is unlocked (different than Releasing) and the pressure ramped down part way, but not all the way to Off;

Releasing takes the TCC all the way to Off;


The GM Service Manuals and Hydra-Matic Technician Guides don't refer to those states at all... showpost.php?p=39479&postcount=5 (http://forum.efilive.com/showpost.php?p=39479&postcount=5)

Log TCCMODE, TCCDC, TSTATE00, 03, 09, 10, 12 to get a clearer idea of what the PCM is doing...

For the TCC to be locked, the TCC Enable solenoid has to be on and the TCC PWM solenoid has to be above 95%.

Apply Enable may mean that the TCC Enable solenoid is on and the TCC PWM solenoid is somewhere between 10% and 90%.


Edit: corrections after reviewing my old logs.


So what does the term slew mean..... exactly? I ask as I have an aweful lot of them cropping up on a recent trans log. I.e Slew then off, slew then off etc.

[MyM8V8]

I'd like to post up this trans log for an expert to have a look. As in my previous post the TC seems to spend a lot of time in "slew" and I would really like to know if this is a problem or kind of normal.

I do not understand the term slew? If it means slipping I need to fix it.

Thanks in anticipation.

[L31Sleeper]

What is the best way to get the TCC to lock up ASAP and stay locked.......
so far I tried lowering the speed in the tables only it seems to stop at APLY EN
and never gets to lock. With the stock tune it locks right on time.

[joecar]

What is the best way to get the TCC to lock up ASAP and stay locked.......
so far I tried lowering the speed in the tables only it seems to stop at APLY EN
and never gets to lock. With the stock tune it locks right on time.When you lower the apply speed you also have to lower the release speed to be lower than it.

[joecar]

I'd like to post up this trans log for an expert to have a look. As in my previous post the TC seems to spend a lot of time in "slew" and I would really like to know if this is a problem or kind of normal.

I do not understand the term slew? If it means slipping I need to fix it.

Thanks in anticipation.Slew isn't really defined anywhere... it seems to mean that the TCC pressure is being ramped up or down...

In addition to TCCMODE, also log TCCDC to see this.

[MyM8V8]

Slew isn't really defined anywhere... it seems to mean that the TCC pressure is being ramped up or down...

In addition to TCCMODE, also log TCCDC to see this.

Thanks Joe. I will :cheers:

[MyM8V8]

Slew isn't really defined anywhere... it seems to mean that the TCC pressure is being ramped up or down...

In addition to TCCMODE, also log TCCDC to see this.

Well my log only shows off and slew. I've logged TCCDC though but it doesn't really help me. Could you have a look and see what you think. The pressure never seems to get to 100%.

[joecar]

Do you have a new log file...?

[MyM8V8]

Do you have a new log file...?

Hi Joe. Here is the log. Please note that the latter part of the log was using dvt.

The first part is conducted in D and you can see the TCCDC never makes 100%, which is why I suspect it remains in Slew (i.e in the ramp up phase).

I dont quite know where the problem is, but I am sure that I should be seeing 100% and the TTC mode shown as on (locked).

[joecar]

That's really weird... you might try reinstalling the EFILive software.