Quick ZF5HP24 question..

[turquise1]

Here is another thing I noticed today when I was looking at Transmission values with INPA. EDS 1 (Main Pressure Solenoid?) actually gets the power delayed when I put the car on D. So I suspected the transmission module but same thing happens with two different modules. Is it possible two different transmission modules would have the same problem? Would something else in the circuit affect their function and delay things?


Meanwhile, the ATF temp was at 15c after staying overnight and the sensor inside the valvebody is brand new (the sensor on the solenoid cable, correct?) so I am not so sure about inaccurate reading. Is there another sensor that I am not aware of?


I am going to start believing my car is possessed soon


Thanks for all the ideas once again,


Ozzie

[RRPhil]

The EDS1 (green cap) solenoid works in the opposite way to the other four (black cap) proportional pressure control solenoids in the transmission. The black cap solenoids increase hydraulic circuit pressure in proportion to the current supplied to them. The green cap (EDS1) solenoid does the opposite. It produces maximum main system pressure when there is no current applied to it and the pressure then reduces as current is increased. This is so that, in the event of an electrical failure, the transmission can limp home in failsafe mode (4th gear) operating at full pressure.






As you rightly said, the transmission fluid temperature sensor is taped into the internal wiring harness.







This is the only temperature sensor for the transmission fluid but theoretically a default value from the engine controller, which is derived from the engine coolant temperature, provides an alternative for the transmission controller to use if this PTC sensor fails. In my experience the sensor reads ‘high’ at lower temperatures. You can see in the graph below that it starts reading at 30°C even when the engine coolant temperature is down at ambient. This was measured two days after the engine was last run



Phil

[turquise1]

Thanks for all the great info. I was reading 25c today in the morning (outside temp was around 10c in Chicago) for ATF and you are saying it is probably normal.



When I looked at how the EDS Solenoids work, what I saw was :


1, 2 and 3 were active at P (744 mA, 780 mA and 780 mA current on each). When I put the car on R or D, I see a brief fall of current on EDS 1 (no change on 2 or 3) down to 650 mA quickly, then head back up to 744 mA briefly, then down to 284 mA and back up to 744 mA. All this takes almost 2 seconds. You can not feel this with R but D has a kick to make it obvious. This makes me think the delay is actually happening at the electronic level rather than fluid pressure. But as I mentioned before this happened with two different modules. As another question, low fluid levels can affect this?


Thoughts?


Thanks,


Ozzie

[andrewwynn]

My transmission oil temp matched ambient temp after sitting overnight.

Edit: I ran the car about a minute before realizing so there's a slight difference showing between radiator out (ambient) and transmission. I'm going to look it up before I start the car today.

[turquise1]

Let me quickly ask. Which Foxwell do you have? Are you happy with it? Comparable to INPA?

[wpoll]

Originally Posted by andrewwynn

[IMG]My transmission oil temp matched ambient temp after sitting overnight

Don't mean to split hairs but that's the inlet temp, not ambient. On my car at least, the inlet temp always seems to be higher than ambient too!

And BOTH are suspiciously close to the 15Deg.C that most of us see as the minimum reported trans temp....

Just sayin'

[andrewwynn]

I goofed actually. The radiator outlet shoes ambient temp not the instake air.

Looking again it was 52 ambient and 57 trans temp but the engine ran for about a minute before I realized I wanted to get the temps.

57f=13.889 c which is close but lower than 15c. 15c is exactly 59 f.

I'll try to get a reading this am to see if it's lower. The overnight temp was below freezing so it should be in the mid 40s in the garage.

[upallnight]

Originally Posted by andrewwynn

My transmission oil temp matched ambient temp after sitting overnight

You got to resize your picture so that they will fit the webpage without having to scroll it

[andrewwynn]

Originally Posted by upallnight

You got to resize your picture so that they will fit the webpage without having to scroll it

That's tap a talk's fault. I'm over 5100 posts I know what I'm doing but a recent update to tapatalk allows multiple photo selection for uploads and if you use it, it skips the resize option.

I use tapatalk for viewing and it auto sizes so I can't tell. Piss poor programming on both tapatalk and vbulletin (that doesn't scale down large photos)

[andrewwynn]

So overnight 11 hours, the car inside was 53, the coolant was 54 and the transmission was 55. The ambient was 48. I think a handful of people must have recently left the 12 bay garage and let in a batch of 30° air and that the average temp of the garage was closer to 54/55 overnight.

55f is under 13c so there is no baseline which would make very little sense.

Somebody out there must live where it's 0f etc and has a scanner.