4WD Problem: update

[sledge]

sounds to me, to be electrical. have you checked the wiring all the way through. is there a sensor on the 4wd???

[gwh200]

all i can think of is what apache suggests further up the thread.if the gearbox ecu is fubarred then it may be contributing to the diengaging of the add.if you can get 12 reliable volts to the soleniod then,its maybe a garbox/gearbox ecu issue(i have engine ecu probs dude,i feel for you)

[darkdezigns]

call me mad,but have u checked the transfer box/mechanical things??

[gwh200]

thats not mad.does the transfer box actually "engage"

[darkdezigns]

thats not mad.does the transfer box actually "engage"

just a thought,as everyone is talkin electrical,and it aint always the case

[gwh200]

have you ttried to engage 4wd with the drive plates off,see if the sleeve is actually throwing forward.

[darkdezigns]

another good way to check is car up in the air,ie all wheels off ground as no stress on transfer etc

[Apache]

I may try and take the 4WD ECU out of the 2 door and see if that is the culpret....not sure how to do what you've just said though...

You say the relay clicks in and out, which suggests that the ECU is engaging and disengaging 4WD repeatedly.

Now, its either doing this because it's getting the wrong signals from the ECU, OR because the ECU is getting the wrong signals from its sensors (ie, road speed too high).

Removing the actuation signal from the relay (the coil connection, you'll need to check whether it's active high or low with a DVM) and substituting it with a known voltage of the correct value should mean you can actuate 4WD without ECU 'consent' if you like.

If 4WD works like this, then the ECU is probably at fault, as there are no mechanical problems stopping 4WD working. If it doesn't work, then the ECU was probably receiving 'no go' signals which relate to a problem with the mechanical side of the 4WD system.

Either way, it should narrow it down.

[MudSurfer]

Unfortunately I don't have the mechanical knowledge to be prodding about with stuff, and I don't have the equipment to take all four wheels off the ground......

Does anyone have a diagram of where all the ECUs are?

[darkdezigns]

Unfortunately I don't have the mechanical knowledge to be prodding about with stuff, and I don't have the equipment to take all four wheels off the ground......

Does anyone have a diagram of where all the ECUs are?

got 4 axle stands??or borrow sum?

[Apache]

I'm not sure testing it with wheels off the ground will show the problem if its ECU / electronics related. There is sure to be a load sensor, and no load will probably muddy the results.

Worth trying, just to see if the problem is still there with wheels off the ground though...

[darkdezigns]

I'm not sure testing it with wheels off the ground will show the problem if its ECU / electronics related. There is sure to be a load sensor, and no load will probably muddy the results.

Worth trying, just to see if the problem is still there with wheels off the ground though...

was thinkin transfer box,with no load it wud likey then kick in

[MudSurfer]

If the black box under the stereo area in the bottom of the centre dash is the 4WD ECU, then I'll borrow the one from the 2 door, as I know that one works, plug it in and see what happens - would this to the trick in terms of narrowing down a fault on that particular ECU?

[Apache]

Are 2.4 and 3.0 gearbox ECUs interchangeable? I assume the gearbox ECU does the ADD stuff too?

If they are interchangeable, then yes, it would indicate where the problem lies. If it works, then your ECU is stuffed. If it doesn't, the problem lies elsewhere, such as a sensor input to the ECU.

[nero279]

Separate control module for the 4wd is behind the trim panel below the stereo/ashtray so only two screws to get the trim panel off then one screw to take the bracket off to get the module out - think it's the larger of the 3 boxes down there but it's got it written on anyway. From what i understand the main gearbox functions are controlled by the main engine ECU.