Think ive found the 4x4 issue (using a tech 1)

[Richiem]

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Hi guys

Finally found a vx dealer with a tech 1 in store today so i got the motor put in to find the cause of th3 4x4 fault i have..
The 4x4 light pops on after around 10mins of driving and it been a mission tracking the fault..

Turns out i have only one code present at its code 74 ( pressure switch failure)
it goes on to say "accumulator pressure below 10 bar code 74 pressure switch "
The pressure on the accumilator should be around 53 bar, so under 10 is
Driving at such low pressure would cause the trans bx clutch plate to slip ( certain death )

Now ive got a new bulb fitted from cav16 so i called richard there ..
He explained that i need to do whoosh test to see if im getting over 25 whooshes of the bulb to see if its pressuring ok..
I did this and it gave me 32 back ( this comfirms its not the bulb)
He suggested the 24mm pressure switch on the back of the accumilator is probably naff, so i should get it replaced
Luckily i had another acc setup in the shed from another car , so i quickily swapped out the pressure switch of mine and then bleed the system..
I have only started up the car since, and ive noticed the 4x4 light goes of quicker than it did before so i need to test drive her tommorrow to see if its resolved the problem..
Must say, im bricking it a bit!
Was it the issue / was it not
Im hoping so

[RobbieV]

[Richiem]

Thanxs mate, its the only issue i have left now, and i just need to get a break!

[Stupink]

Glad you found the probable source, didn't think it would be camber related. It is possible to read the codes yourself sometimes, I have forgotten entirely what years you can/can't read them, and what bits it is that you can/can't read on them. I've only ever had fairly early turbos and you can read all the fault codes on them ecu/abs/4x4 etc.. but anyway at least its done.
seem to recall i had a pressure switch faulty once before myself and it gave similar symptons, think i had a dodgy solenoid once too do a similar thing, but either way the electronics are all fairly basic so shouldnt cost you much to replace a few other bits even if this wasnt the only fault

[cornishtaz]

fingers crossed for tomorrow

[Stupink]

thats wouldn't supprise me at all if they did it for that, its a shame, i love my early turbo's. its just so easy to fault find, i keep the paperclip in the car and the fault codes on my phone to do on the fly repairs lol.

[Richiem]

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AARRGHH!

Just got back from run to doncaster..
4X4 stayed on for about a minute, then the light came on.
Doesnt work at all now!!
Light stays on all the time.
Before it stayed on for a few miles then cut off..
Only thing im hoping is, the replacement switch may of been a total dud..
Worst thing is, you cannot get a new switch anywere anymore, so i have to use 2nd hand ones..
Dont know what to do next as im getting a little p`d off with the whole thing now..
Would anyone know if there is a way of testing if the switch is bust or not using a meter or something?

Cheers rich

[Phantom]

could Cav16 not help?

[Stupink]

Its a bit late, so i wont make much sense, but if the sesnor tests ok check the solenoid itself, i have vauge memory of the two faults being linked somehow as far as the ecu is concerned. i may be wrong.

[Richiem]

The actual fault was code 73 which is told as pressure switch low / pressure under 10 bar..
Now as far as i can see, the pressure should be ok as the acc bulb is brand new and passes the over 20 oumps of brake test very well..
The original switch may of been ok..
When i was starting up and driving , the 4x4 light would come on after around ten mins giving the code 73..
I do have another solonoid spare so i may also try this..
What really doin my head though is the 4x4 worked perfect when i had the bad camber and worn rear tyres fitted!
Seems since i turned the 4x4 of for 3 months and corrected the rears , now its giving me these codes..
Dont make sense this happening as i never touched any of the system

[Stupink]

Sounds like teh wrong code mate, I think its probably more likely your footbrake switch, dont even try to "test" it, as they always appear to work fine, but if you have a spare swap it out, if not go pick one up and swap it over.
73 as far as i know is "73 Car stopped without using brakes from speeds greater than 37mph" so presumably it only thinks brakes arnt used as switch is dufferoo. could be wiring of course i suppose. (twin pole switch so brakelights work seperately, also brakeswitch usually seems to function ok on a multimeter but can still give codes)

[Richiem]

Sorry guys , my head is all over the place, its code 74 not 73..

[Stupink]

Ahh.. well that one is low pas as you say then yeh,
Is the sensor on the accumulator circuit or the pas supply circuit? I can't remember... perhaps if you have a slack pas belt or dying pump you may occasionally be dropping below 10bar and setting the sensor but still getting your whooshes overall? but then on a late setup its wide belt isnt it so only really dying pump or airlocks would be plausable, belts either on or snapped..
Do you ever notice any noises from the pump? or suffer stiff steering momentarily?

[Richiem]

Will check this one out stupink..
This is a new one i havent been made aware of yet.
Thanxs

[Richiem]

The sensor for the pressure on the 4x4 system is on the back of the acc block ( 24mm bolt with 2 pins)