RRH

A friend of mine asked me to have a look at his STi5 Type R, which appears to have a strange centre diff problem.

I'm used to seeing them with flaishing lights, but this one appears to be ok electrically. The wheel moves freely along with the corresponding dash lights.

When manoevering slowly it is behaving like the centre is still partially locked, and is dragging a rear wheel if that makes sense.

I haven't driven it yet myself, but have asked my mate to try the handbrake test with diff both free and locked to see if it realeases it.

Anyone got any ideas?

johnfelstead

it will feel lik ethat if the centre diff is set outside the green lower settings. Lifting the handbrake will also release the diff and stop this. If it doesnt then you have a problem. When the centre diff controller fails its normal for the diff to be fully open, so get him to check he isnt using it in the yellow when doing slow manouvers.

gravelexpress

yup this is my car -

on lowest green at slow speed turns as described above the rear wheels sometimes crab and I can hear clunks
at speed on lowest green its rear end is easy to push out and get into a tank slapper

on next green at speed it is a lot more stable in the wet

I did a test this afternoon - low speed turns as i moved dial forward into orange it meets resistance you can feel the diff wind up, if i move the dial back to green it frees up

but

if i repeat the manouvre and try and release the diff using the handbrake it will not free up.

gravelexpress

to help diagnose the problem -

i thought-
if i was to disconnect the DCCD ECU am I correct in that it will default to OPEN setting as no current will be going to the DCCD unit?

I could then see if the car is still partially locked on the rear diff?

anyone - esp Mr Felstead

Adam M

I was about to suggest it.

In order to make the conditions as bad as possible you want the lowest speed possible and the tightest lock.

Dissassemble the centre console so you can access the diff control and as you are actually turning, unplug the diff and see if you can feel the difference.

As you say the default position should be completely open (not quite).

Good luck.

gravelexpress

I just checked the wiring within the handbrake console to make sure the pot was connected properly. could not tell if the handbrake switch was functioning properly - the handbrake requires adjustment. I will have a look for that DCCD ecu later - what does it look like? and where do i find it

Adam M

dont think you need to worry about the dccd ecu, just unplug the switch and the circuit break should force it into open mode.

The handbrake is an override, it shouldnt ever override to force it to stay locked, only open.