F4 - "Limp home" mode problem , but with some curiosities.

[Edward]

Eagerly, I whipped off the solenoid valve body and checked and cleaned it. (knew nothing about error codes) Reassembled the front of the car and conducted three oil changes on the gear box until I had clear fluid. All the impedance reading for the solenoids were to spec. This enabled me to driver the vehicle to the Service Centre and get the following error codes: P0740, P1844, P0732, P0733 (see, I'm learning)
Now these codes imply a gearbox that has gone poopoo, ..... but here's the thing:

If I stop and start the car each time I get the F4 error code (ie. the box has not changed up until it clunks into limp home mode) and I repeat this 4 or 5 times (ignition off then on), the gearbox works beautifully for the rest of the day .... and with no slipping.

Aside from the fact that I will now replace the gearbox, my theory is that the speed sensors are malfunctioning while cold and then behave as they get warmer.
I bought this little girl for $300 and have thrown another $300 at it (includes a thermostat) so am still eager to give it some life. Hope someone finds these observations interesting
Ed

[LRT]

Have you tried operating the gearbox manually using 'Command Shift' ?

[Edward]

Yes, have tried every combo known to man. The box continues to end up in F4 mode until four to five On / Off ignition cycles. Only then does the box return to normal opperation.

[LRT]

That's extremely frustrating! What about trying to skip a few gears? Seems like there's a bit of a glitch happening.

How old is the battery and/or does it go flat quickly? I've found the electrics in some Volvo cars go silly if the battery is on the way out.

The other thing is you could leave the battery disconnected for a while to see if it resets the computer. But make sure you have the radio code before you disconnect!

[LRT]

This link may be of help: jatco drive in 1 and 4 only | LandyZone - Land Rover Forum (https://www.landyzone.co.uk/land-rover/jatco-drive-in-1-and-4-only.192505/)

Sorry I don't have much experience with the JATCO autos as I prefer manual gearboxes. However, I may end up getting one for parts as they're very cheap. It'd be interesting to see what was involved with the manual gearbox conversion Land Rover did for the M-Sport V6 rally cars.

[Edward]

Thanks for the hints, but battery new and I also have tried every sequence of manual shifting.

So here is my latest suspicion.

As I have said, Stopping and starting the vehicle 4 or 5 times over a 10 minute period restores the gearbox function to normal ......... the clue is time.

So instead, I simply ran the car for 10 minutes in F-4 "Limp home mode", then restarted. ....... ie the same time to warm up ....... and the box worked normally.

I am thinking that I have a faulty speed sensor (any one of the three) that is sensative to oil temperature. .......... sadly I need to remover the whole shebang to check and replace these.

In the mean time, I have picked up another Freelander with a supposed working box for $400, so there is going to be some swapping. When I pull down the original box and check the speed sensors, I will post my findings.

Now all I have to do is get this new vehicle from Jindabyne to Adelaide ?????

[LRT]

Edward, I know the pain! I've just bought a Freelander diesel with a manual gearbox and on the 2 hour drive home it's gone and done the synchro's and Has lost fourth gear. Now the box is going to have to come out!

It does sound like a sensor issue. The other thing is there could be a corroded connection somewhere that is causing too much resistance.

[LRT]

I am thinking that I have a faulty speed sensor (any one of the three) that is sensative to oil temperature. .......... sadly I need to remover the whole shebang to check and replace these.

In the mean time, I have picked up another Freelander with a supposed working box for $400, so there is going to be some swapping. When I pull down the original box and check the speed sensors, I will post my findings.

Now all I have to do is get this new vehicle from Jindabyne to Adelaide ?????

Hi Edward,

How did you go?

[Edward]

Sorry for the delay in response . ......... Had a kidney ripped out, battled the spread to the lungs with new drug, only to find my Pituitary gland was damaged in the process ........... but all good now.
As to the Gearbox, I stuffed up the purchase, so didn't get the replacement. So still driving around with mine. (still needs 10 mins to warm up before changing.)
A further enquiry is regarding a metal breather tube that exits the back of the box, between the firewall and the box. It just sits there in the middle of nowhere, begging to be connected to something.
I'll repost this in a sepparate querie.

[tonym]

Hi, Any luck with the gearbox? I have swapped all my solenoids and the sensors and solenoids all give resistance values in the correct range but I still have the problem that it will only change properly once it has warmed up. Any clues would be welcome.

[ian338]

Did you replace the sensors or just the solenoids? Last post a bit ambiguous. I have the same problem and looking for answers too