Hello,
I was leaving a store earlier today and got the GREARBOX FAILURE warning light. Checking with the OBD reader I see it's a P1746 code. " Pressure Control Solenoid 'A' Open Circuit" . I'm wondering if it's a TCM or the transmission itself? I have both another TCM and transmission but am more inclined to think it's the tranny. I have seen posts of guys replacing these solenoids and am trying to decide if I should replace the parts or just bite the bullet and replace the transmission. If someone could point me to those posts I'd appreciate it a bunch!
Thanks much, Dave
Oh, it's one of my 2000 VDPs.

 

I will probably replace the solenoid instead of the entire transmission. Checking at the local parts houses, seems that the supply of Pentosin ATF fluid is unavailable unless ordered. What else can I use instead? I have about 2-3 liters of Pentosin fluid at this point and would not want to mix it with something different. Any suggestions?
I'd like to get this fixed tomorrow or over the weekend before Thanksgiving....

 

What's the mileage?
Did you ever do a (complete) ATF change?
If yes, when and which ATF did you use?
Did you check your current ATF level (with car jacked up level and the engine running it should just drop out of the filler plug a bit ATF temperature around 40°C)?
Do you have ATF leaks?

 

I wouldn't jump to conclusion that it is either TCM or the Solenoid. "Open Circuit" could also be due to bad contact in the connector to the TCM or in the connector to the transmission. Perhaps you should first clear the code and see if it reappears (and how soon). Also inspect/clean the mentioned connectors.

 

Hello M. Stojanovic,
Well that sounds like a good idea! I went to move the car this morning and the transmission seems fine. I was even able to clear the code. I think I'll check the connections before changing anything at this point or swap the TCM. I have a TCM and transmission from my wrecked 2000 VDP so I's think everything should be OK to swap.

To Peter of Australia, I changed the fluid probably 50,000 miles ago with Pentosin fluid and had the car on stands and level. I've probably changed fluid on these cars a number of times and it's always a pain!
Guess I try the connectors and see if it has a continuing problem. Is there any way to measure the terminals across the solenoid without removing the pan? Would be an interesting check to see if one is out of measurement from the other two.
More later....Dave

 

I measured between the pins to each of the solenoids and Solenoid valve +ve on the TCM connector to determine if there was a problem with circuit integrity. All three measured 35Ω, (within a tenth), so I'm inclined to think the transmission connector is intact and solenoid is probably failing intermittently. The P1746 code, (Gearbox Fault) popped up a few weeks back when my wife was driving this car, (J2). Since then I'm driving it and she has the other red VDP. Actually, I drove it to Florida last week and had no problems at all. Guess I'll have to fix it though. Thinking the weather is rather mild today...If I wait a few weeks it will defiantly be colder in the garage!

When I got the warning yesterday, I pulled over to the curb, powered the car off for about a minute, and when I restarted, the code was still evident. It seemed that the car was not in first gear when I began to move foreword. This morning when I started the car and it was OK and I was able to clear the code. Intermittent problems! Doh!

 

I should have added one more question to my list: I do not know, which transmission is in the 2000 VDP...
Each Jaguar transmission requires a VERY specific ATF. Using a multi-vehicle ATF for a Jaguar is (at least for me) an absolute No-No.

Here is my DIY-guide for changing (full flush) of the ATF.\:
https://www.jaguarforums.com/forum/x...-flush-265900/

My transmission is the ZF 5HP24. The possible ATF for this one are:
ZF lifeguard fluid 5
Esso LT71141.
Mobil LT71141
...and pretty much nothing else!

So maybe your issues are due to low ATF and/or wrong ATF.

 

Even though your readings were good at the time, the transmission connector may have "latent" intermittent contact for the solenoid in question. The connector is prone to developing ATF leaks which "flood" the pins which may cause intermittent loss of contact. So, before "digging" into the solenoid, I would first inspect the pins of this connector and make sure they are all good and clean. The same goes for the TCM connector.

With regard to the Solenoid, its windings could also have an intermittent break. I had such a case on one of the solenoids in the transmission of my Saab 9-5 - occasionally, it would fail when hot and be back to normal after transmission cool-down.

 

Hollo,
To bring this up to date: I decided to remove the pan and start the repair so got out the drain pan but found the drain plug was not tight. I mean only finger tight. I probably did not tighten it last time I changed the fluid about five years ago! The car had been occasionally leaving a drop or two of fluid in the garage for a few years so perhaps it was low? Ended up putting in about a liter of fluid. The car seems to drive fine but have not driven it but a few miles since.

It was not leaking at the transmission connector and the plug was in tight as well. It looked clean around there. I certainly will check the connectors on the solenoids and where the harness enters the trans body too. You are correct, there could be a weak connector, or worn wire to blame.

I have also decided I will drain & refill the transmission anyway and while it's apart, change that solenoid and check all the connectors just to cover the bases. Will be good to have that peace of mind.

As for the fluid; I've used Pentosin in my five XJs for the last 15 years with no noticeable problems. Have not tried to find the other fluids and since what's currently in the car is mostly pentosin, will probably stick with that.
Thanks to all you guys for responding! The forum is invaluable to use folks trying to keep these old cars going!

Best, Dave

 

Well, there are plenty of threads/discussions about the right ATF...
I'll stick with the right ATF.
So it looks like low ATF was your issue.
And there is this correct procedure of how to fill the right amount of ATF into the transmission (jacked up level and engine running)...