Hicas Misbehaving Randomly

[blind_elk]

The HICAS in my 32 has been acting up recently. It will randomly steer the arse end left for a second or so, then go back to normal operation.

It seems to be most likely to behave like this after cold starts. It is most likely to do it on left turns, and occasionally when travelling straight. It never seems to do it for right turns.

There is no error light showing up on the dash (and yes the globe is working). I can't seem to get the system into diagnostic mode, as per the tutorial. But I'm guessing if there is no warning light, then the diagnostics isn't likely to tell me anything.

This morning, I unplugged both boxes under the rear parcel shelf to "reset" them. It seemed to help, until on a straight bit of road the car suddenly "crabbed" left for a second, then recovered.

Nothing on the car has been changed that might contribute to the behaviour.

Anyone have a solution (excluding "fit a lock bar")?

TIA.

[MBS206]

Are you sure HICAS is stuffing up? Go and get a wheel alignment done.

You may find your rear alignment is way out.

[GTSBoy]

Do you have a different steering wheel on it? If so, does it have a drive pin behind the boss to drive the steering angle sensor?

I ask this because, 11+ years ago when I first got my R32, it behaved similarly to yours. It would generally be fine, but then at random times above 80km/h it would suddenly steer the rear end so that you had to crank on a 45° of lock to hold it straight. It would stay like that until power cycled, and then it would probably do it again the very next time over 80.

I got it into diagnostic mode eventually* and it reported steering sensor. I tested the sensor and it was fine, but the whole process took me quite a long time to realise (duh!) that my Momo wheel was not driving the sensor. So the HICAS system was panicing at random intervals.

All I did to fix it (given that HICAS is shit) was to pull the smaller of the two plugs off the HICAS computer and it never did it again. That's the budget way to deactivate HICAS.

Now, in your case, you may be having a problem caused by another issue. The original Nissan Australia R32 GTR manual had a supplement bulletin put into the front of it warning all service techs to pull the HICAS computer out, take it apart and put some locktite on the screws inside. Apparently there had been a number of failures where screws came out, roamed around inside the casing and caused shorts that sent it all to shit. Including behaviour like you report. Your cars is so much older now than when that bulletin was written that something similar might have happened, or a solder joint might have cracked.

Another thought is that the solenoid valve on the HICAS lines under the car might be failing and randomly letting strange things happen.

My advice. Seriously. Deactivate HICAS completely. Lock bar at minimum. Pull it all out in ideal world

* This was actually part of how I found the problem. You can't get it into diag mode unless teh steering sensor is working, and I had the steering wheel off and moved the senor manually - was the only way to get the thing into diag mode.

Edited August 9, 2011 by GTSBoy

[blind_elk]

Do you have a different steering wheel on it? If so, does it have a drive pin behind the boss to drive the steering angle sensor?

Has a Nardi Torino, which was on the car when I got it back in 2000. (as I stated in OP, nothing has changed recently)

I ask this because, 11+ years ago when I first got my R32, it behaved similarly to yours. It would generally be fine, but then at random times above 80km/h it would suddenly steer the rear end so that you had to crank on a 45° of lock to hold it straight. It would stay like that until power cycled, and then it would probably do it again the very next time over 80.

This will do it at speeds BELOW 80, often around 60.

I got it into diagnostic mode eventually and it reported steering sensor. I tested the sensor and it was fine, but it took me quite a long time to realise (duh!) that my Momo wheel was not driving the sensor. So the HICAS system was panicing at random intervals.

Worth considering. Maybe a pin has broken off.

All I did to fix it (given that HICAS is shit) was to pull the smaller of the two plugs off the HICAS computer and it never did it again. That's the budget way to deactivate HICAS.

As I said in OP, I don't want to deactivate HICAS. That just masks the problem, it doesn't find the cause.

Now, in your case, you may be having a problem caused by another issue. The original Nissan Australia R32 GTR manual had a supplement bulletin put into the front of it warning all service techs to pull the HICAS computer out, take it apart and put some locktite on the screws inside. Apparently there had been a number of failures where screws came out, roamed around inside the casing and caused shorts that sent it all to shit. Including behaviour like you report. Your cars is so much older now than when that bulletin was written that something similar might have happened, or a solder joint might have cracked.

Worth considering.

Another thought is that the solenoid valve on the HICAS lines under the car might be failing and randomly letting strange things happen.

P/S fluid appears to be ok, might now be a bit overfull after I added some fluid, but pretty sure it was actually ok to begin with, so not losing P/S fluid.

My advice. Seriously. Deactivate HICAS completely. Lock bar at minimum. Pull it all out in ideal world.

As I said in OP, I don't want to deactivate HICAS. That just masks the problem, it doesn't find the cause.

Thanks for your input.

[GTRAAH]

Im thinking of getting another steering wheel aswell is there something i have to watch out for when i buy one? I do not want to dissconnect hicas

[GTSBoy]

Well, yeah. I imagine that it's almost impossible to get one, but you have to get a boss kit that is specifically for R32 with HICAS (and possibly a range of other HICAS cars of the same era that used the same sensor - I don't know if there were different sensors in the S13s, or in the 33s, etc).

Or, you could try to add a drive pin onto the back of a non-suited boss. But I don't know what the best way to do that would be.

I must ask.....why all the HICAS love? It is shitful. Cars without it are much nicer to drive, especially when punching along hard.

[blind_elk]

Ok, so I've tried a couple of things.

First, I disconnected the HICAS ECU - that's the small box, held in by 3 bolts, and connected to 2 plugs, right? Anyway, no loose items floating around inside. Opened it up, looks ok.

On the road, the steering is now noticeably heavier (but not like no P/S at all). And the rear end is questionable as to its stability.

Tried to check the HICAS sensor in the steering wheel - couldn't get the fn steering wheel off! Despite the retaining nut was quite loose, the wheel is firmly attached to the steering column.

I'm beginning to lean towards a worn component - tie rod, etc - being the root cause of all this. I was told some time ago that there is a bit of wear in the inner joints in the (front) steering rack, so should check that further as well.

[85URK]

I had a similar thing happen in my 33 gtr with the hicas, i removed mine now and have a lock bar in place now. but it was like a split second twitch in the rear end like the rear end steps out then corrects itself?

I have not found a reason for this either, but maybe something internally inside the hicas unit itself, like missing or skipping inside, giving it a dodgey reading.

[Dohmar]

Same thing happened to me in my 89 GTR. I did a lot of research on HICAS and considered a lot of things before finding out that the problem was staring me in the face (literally)....

Hicas is always reading data. Some sources cite that it only activates at 80kph but that is a total furphy. Try navigating a single lane roundabout with hicas and without at 60kph and you'll see what I mean.

My hicas would try and work up until a certain point, approximately 10km from the moment I turned the key. From that moment the error light would come on and I'd be wondering wtf was going wrong. After the 10km, I was safe because the hicas mechanism was locked straight ahead by the hicas computer.

If I was to exceed 80kph BEFORE this time however, thats when the 'crabbing' and 45' turn stuff would happen. Near my house is a 80kph section.... I'd be driving along and as soon as i hit 80kph *bam* the hicas computer changed 'maps' and decided that the steering angle sensor was off.

It wasnt.

It was the boss kit. 32 GTR's changed their speed sensors sometime, not sure what year but there are definately different boss kits for zenki, chouki and kouki GTR's. I'm not sure which has which, but one has the magnet/sensor at a 3pm location on the steering column, the other one is 6pm. Or something like that.

All I know is - once I replaced the boss kit for a zenki (early aka '89) series, hicas started behaving itself. I only use the car for street driving and the very very very very very occasional track/drag work so I've opted to keep it. I've gotten used to it tbh and its not so bad.

Once you get the proper boss kit, you'll be able to initiate the hicas diagnostic blinks... that can also help you - I tried for months to get my hicas in diagnostic mode with the wrong boss kit. Needless to say, I felt like punching myself in the face once I figured out what was going on...

Good luck!

-D

*** Edit - Incidentally, the reason it 'crab walks' and you need to snatch it 45' or whatever, is that the hicas computer has been reading the steering angle incorrectly. When travelling in a straight line it think you're turning, and eventually decides 'surely the car cannot be turning in circles ALL THE TIME?!?' and then deactivates itself. Before this happens, the car thinks its travelling in a slight turn (relying on the steering angle sensor alone, hicas responds harder when the G-sensors actually tell the car you're going sideways), which is why the moment it hits 80, the rear toes left or right (depending on the incorrectly percieved angle) and you shit your pants and yank the wheel to the side just so u can stay straight.

[blind_elk]

Solved! (well, once I get a replacement part it will)

I had noticed that it appeared to misbehave when the front right corner was loaded. I had thought it might be the upper control arm bushes (adjustable camber bushes) having collapsed, causing dynamic change to the toe-in. However, when I jacked it up today, I found:

The split pin has somehow come out of the outer ball joint, and the retaining nut has started to undo. So it wasn't the rear end that was turning out, but the front end turning in.

[GTSBoy]

Well there you go. I suppose we should never assume that it's HICAS when there are so many other conventional steering/suspension parts in need of urgent attention? Just as well you found that - could have been nasty and come off at speed and you'd be scenery.

[blind_elk]

I'm trying to get some replacement ball joints through Bursons. They got some in from interstate, but they look nothing like what I have.

Anyone able to confirm the correct part number for a replacement lower balljoint, RH if it matters, for a R32 GTS4 RB20DET. Nissan gave me 40160-05U00. And they want $170!!

Also, what is the part number for the R32 GT-R equivalent?

Tx

[GTSBoy]

Surely it's the same part number as it's the same front suspension?

[blind_elk]

Might be the same part, but not necessarily the same part number.

[blind_elk]

Yes, solved. Re-fitted the joint after cleaning up the thread, then took the car through one of the corners where it used to misbehave, and it didn't.

I guess the moral of this story is never guess that the technology is always at fault.