Tccdc Pid

[DrX]

Does the TCCDC PID reflect actual TCC activity or is it just 1 factor in TCC engagement? I have logged TCCDC at 95.3-97.3% at all times other than below 1500 RPM in first gear where it is 0. Even in first gear, above 1500 RPM, it is at 95.3%. Is this normal? I don't see anything in the tune that would affect this?

[DrX]

To answer my own question... I think that the TCC apply solenoid activity is what I have to log to monitor actual TCC engagement(still have to find the correct PID). I believe that the TCC Duty Cycle just reflects TCC PWM solenoid activity which only modulates the character of TCC apply. It looks like TCCDC is active at any RPM over 1500 even when TCC apply is off. I guess that way its always ready when the apply is commanded.

[joecar]

You said it correctly:

TCC solenoid is used to gate the TCC PWM solenoid;

When the TCC solenoid is on, the TCC PWM solenoid is used to ramp up the TCC apply or to ramp down TCC release.

PCM first ramps up and then down the TCC PWM solenoid DC before enabling TCC solenoid.

(see diagram)
In first gear, at approximately 13 km/h (8 mph), the PCM operates
the TCC PWM solenoid valve at approximately 90 percent duty
cycle (point S on the graph at left). This duty cycle is maintained
until a TCC apply is commanded. When vehicle operating
conditions are appropriate to apply the TCC, the PCM
immediately decreases the duty cycle to 0 percent, then increases
it to approximately 25% (see point C on graph). The PCM then
ramps the duty cycle up to approximately 50% to achieve
regulated apply pressure in vehicles equipped with the
Electronically Controlled Clutch Capacity. With the ECCC
system, the pressure plate does not fully lock to the torque
converter, instead a consistent slip of 20 to 40 RPM is regulated.
The rate at which the PCM increases the duty cycle controls the
TCC apply. Similarly, the PCM also ramps down the TCC
solenoid duty cycle to control TCC release. Under some high
torque or high vehicle speeds, the converter clutch is fully locked.
There are some operating conditions that prevent or enable TCC
apply under various conditions (refer to the Automatic
Transmission Fluid Temperature sensor description). Also, if
the PCM receives a high voltage signal from the brake switch,
signalling that the brake pedal is depressed, the PCM immediately
releases the TCC.

[DrX]

Thanks for that information!

[joecar]

You can see from these diagrams that the TCC PWM solenoid indirectly regulates TCC apply pressure which is then gated by the TCC solenoid into the TCC.

[joecar]

...(still have to find the correct PID)...

See the following PIDs for TCC Solenoid state:
TSTATE0
TSTATE1
TSTATE9
TSTATE10
TSTATE12

"TCC Solenoid" and "TCC PWM Solenoid" are the newer names for "TCC Enable Solenoid" and "TCC Apply Solenoid".

[DrX]

See the following PIDs for TCC Solenoid state:
TSTATE0
TSTATE1
TSTATE9
TSTATE10
TSTATE12

"TCC Solenoid" and "TCC PWM Solenoid" are the newer names for "TCC Enable Solenoid" and "TCC Apply Solenoid".

Thanks again. These PIDs were the only reference I could find to the TCC Solenoid as well. I will try logging them.

So far I have only seen TCCDC at 0(low speed 1st gear) or varying between between 95.3%-97.3%. I have never seen it at 50% or 100% but maybe the transition occurs too fast to be captured by EFILive. 95.5% is what I see at low to moderate TP values, 96.1% at WOT and 97.3% under low TP/decel conditions. TCCSlip seems significant most of the time except during decel when it is low or -ve, but I assume that is the result of the 2600 stall converter.

Nice schematic.

[joecar]

Also look at TCCMODE pid whose values represent the various lines on the TCC apply diagram (in between the points A, B, C, D....).