P38 Ratio Control Motor

I am having problems with my P38 4.6 HSE, sticking in low range.

Reading the workshop manual is states that the position switches on the ratio contol motor are fed a 5V feed from the ecu, but it does not state wether the actual motor drive supply is 5V or 12V.

Any assitance with this would be greatly appreciated, I was going to stick 12v on them motor contacts to see if it runs, but if its only a 5V motor that might not be such a good thing !!

Thanks in advance

Rob

If you are talking about the high/low drive motor on the transfer box, I took mine off, dismantled the contacts part (carefully) and found that the grease inside had gone solid and was stopping the motor going to full travel. Cleaned it out re-greased and tested with 12 volts worked fine so refitted and no trouble since. The problem is that not many people ever go into low range and the thing siezes up. Mine gets plenty of use.

Thanks for the advice, I've now done as you suggested, and the motor runs back and forth quite happily.

I have refitted it to the car, and I still have the same issue - if I connect up the harness connector it immediately moves to low box and stays there. If is dissconnect the harness and power the motor externally I can move the selector back to high box, and it seems to drive ok round the yard.

The instrument panel is saying select neutral, and where ever I move the stick to it remains in low range. When I move the selector to neutral and then move it through the gate to the high range position I get a gearbox warning light on the dash, and the electrics appear to flicker slightly on the dash. I am now wondering if I either have a short somewhere, or is it an ECU problem.

ANy more insight into the wonders of electrics would be much appreciated.

cheers

Rob

If your still in low box when you connect the harness before you connect the harness put it in neutral in low box check dash says nuetral should bleep 3 times with gearbox warning cogs flashing 3 times when it stops move across to hi range it should bleep 3 times with gearbox cogs flashing when it stops the dash should say high each time you stop the car put it into nuetral and slide across it should bleep three times with cogs flashing when they stop flashing and dash indicates you are in low the procedure has finished and vise versa.

If you change from one to the other Hi to lo or vise versa and the dash doesn't change its jammed

Check the transfer box ECU for signs and smells of burning.

Datatek said:

Check the transfer box ECU for signs and smells of burning.

Click to expand...

Hoping its not that just wanted to clarify what's its doing .

defender300td1 said:

Hoping its not that just wanted to clarify what's its doing .

Click to expand...

If it motors to low when plugged into the ECU but works normally with 12 volts applied direct it's a pretty good bet that the ECU has failed unless the switches are miss timed, even then it should not motor unless it's in neutral.
The ECU's are a common failure item and cheap on Ebay.

Op found this for you you can change to hi or low your self with motor off . Test your ecu with this guide note if motor is weak it won't change ratio .