Transmission OBDII Code P1747
 

I had been working hard to narrow down my poor idle problem and feeling better about the car I elected to drive it a little more. In doing so I noticed that the trans was lurching a little at cruise speeds at 70, 55, 35 & 25. Yesterday I get a call from the wife that she got a Transmission Fail and a limp home on the dash, she was just down the street and I went to look and pulled a P1747 code. I cleared the code restarted the car and all was good I could get it home. I checked the codes again when I got it home and found no additional codes so I elected to drive it to see what I could find and in less than a mile it came up again P1747 & P1643 and the P1747 would not reset so I would say it is broken.

A little history the trans was rebuilt and a reconditioned valve body was installed about 2 ½ 3 yrs ago and all was good with the exception of the poor idle that was taking place.

I can use a little input on what might be going on with the trans I know little about auto transmission but I got a feeling I am about to learn like I did with the A/C system. I replaced the battery the other day because it was over 3 to 4 yrs old and I noticed lower voltage and I was comfortable with that.

Hi Gus.


Kind of reluctant to give you any advise as you are one of the experts here.
But anyway, here is what I would do.


P1747 indicates problems with pressure regulator number 3.


Disconnect and clean connector EM46, especially check pin 7. Round connector located aft left transmission housing. Don't undo the whole connector from housing. Then your fluid will leak out.


Disconnect and clean connector EM7, especially check pin 29. This is the one connected to your TCM.


Use dedicated electrical cleaner, not WD40.


Next I would change pressure regulator number 3. This can be done with transmission in car after removing pan.


It could also be an internal failure in your TCM. I don't know if they can be rebuilt.


P1643 is a communication failure between TCM and ECM.

Thanks this is what I had in mind to do. I am thinking it is the coil pack on the TCM but not sure until I remove the pan. I am in search for a pinout info on the coil pack that I think I have just need to find it this way I can check the TCM coils without opening the trans.

I am not an expert just provide a lot of input and this time I need the input.

Hi again.


Just to avoid any misunderstanding, the TCM (Transmission Control Module) is located together with the ECM.


The coils or solenoids are located at the valve body inside the transmission.

I knew that! "TCM (Transmission Control Module)" Just a brain f__t! Thanks!

I am presently waiting for a phone call from the shop that rebuilt the trans. I want to ask a few questions about the valve body that was installed but any additional information or suggestions will be accepted.

Hi Gus.


This is the most extensive thread I have ever read. Lots of good pictures.






ZF 5HP24 teardown

Thanks for the info! I had seen that post years ago on Land rovers forum and it was well done. I did a little research and made a few calls to the transmission shop and ZF and have a plan. I am going with the electrical first and will see where it takes me.

I should mention the code is suggesting it is electrical

Gus - you may want to look at the wiring harness first. Had my tranny rebuilt last May/June and ended up a few months later with a P1747 & gear box fault - cable harness had been reused and failed having to be replaced.

I am taking it from the trans to the TCM