7427 handle relay with tcc pin

[myburb]

What I want to know is do you think the tcc circuit can handle a standard bosch automotive relay. I am wanting to use it in my manual tcc circuit to drop lock up at a predetermine road speed whether it is manually locked or not. The question is not so much will it work as can the pcm handle the load.

[1project2many]

Absolutely. In older THM400 equipped trucks the TCC pin controlled a relay to the kickdown solenoid.

[myburb]

Thanks. It's all wired and the chip is burnt so test drive shortly.

[Nasty-Z]

As stated , it will work fine . I always use the output to trigger a relay , just for another piece of mind in the circuit.

TOM

[myburb]

All works as planned but for one curve. I never anticipated the amount of PWM that was going on with the engage and disengage. It makes the relay chatter. I don't see anything in TP that allows elimnation of the delay. Anyone know how to change that? I will do some searching in the hac's.

[Six_Shooter]

On a simple on/off TCC, yep a relay will be fine, but on a PWM based TCC control, a relay will not work and will require a solid state relay or semi-conductor (I.E. Transistor) based solution.

What are you trying to do? The PCM should be able to control the TCC directly, without the need for a relay.

[myburb]

For the last 3 month I have been set up to have tcc by ecm or manual and have preferred manual for the areas I operate. So this experiment was to have lock drop out at 20 whether the manual switch was on or not. Thinking of a panic braking situation. Connected to the brake switch wasn't what I wanted as I have a couple of slow steep hills and with a trailer 2nd loc with brakes on works good. I normally use a 94 6395. For this test I used a 95 7427 with the same chip as the 6395 but each had the limp part of their original chip. Do you think there would be any difference in the tcc PWM handling between the two?

[myburb]

Well the experiment was a bust in a couple of ways. First regarding the PWM making the relay chatter and second was I didn't think far enough ahead that even though I was just powering the relay from the ecm tcc control it still unlocked the converter when I applied brakes. I need to find another speed sense circuit to control the relay. As a side note I was amazed at how much PWM went on and how it varied depending on tps/load.

[myburb]

Added note from testing if you leave it manually locked and you come to a stop as it shifts to 1st and pulls the rpm down to about 500 the converter unlocks. I didn't test panic stop so can't comment on that.

[lionelhutz]

Which transmission was the bin supposed to be controlling and what mask are you using? 4L80e transmission? 4L60e applications shouldn't use PWM on the TCC solenoid. In 95 GM added a new PWM solenoid to the TCC circuit in the 4L60e to control the lockup pressure.

If it was a 4L60e bin then maybe you were on the PWM solenoid pin instead of the TCC solenoid pin? Pin E11 instead of E10?

Still, if there is PWM on the TCC solenoid then the bin must have a table/scalar/etc used to set the PWM rate so in theory it could be adjusted to just be 0 or 100%.

I have done a few setups with PCM TCC control and no brake switch wiring to the PCM or in the TCC circuit and they have behaved fine even though the brakes don't unlock the TCC.

[myburb]

It is 6395/7427 $OE 4l80e BHDF
]Which transmission was the bin supposed to be controlling and what mask are you using? 4L80e transmission? 4L60e applications shouldn't use PWM on the TCC solenoid. In 95 GM added a new PWM solenoid to the TCC circuit in the 4L60e to control the lockup pressure.

If it was a 4L60e bin then maybe you were on the PWM solenoid pin instead of the TCC solenoid pin? Pin E11 instead of E10?

Still, if there is PWM on the TCC solenoid then the bin must have a table/scalar/etc used to set the PWM rate so in theory it could be adjusted to just be 0 or 100%.

I have done a few setups with PCM TCC control and no brake switch wiring to the PCM or in the TCC circuit and they have behaved fine even though the brakes don't unlock the TCC.[/QUOTE]