It's a quick one... does the ECU control the HICAS system? I read that HICAS is /supposed/ to only work over 30 mph, yet Henri finds it works much lower. AndyP's comparison chart says UK spec has a high-speed version of HICAS. So is it all down to the EPROM code? And can it be tuned?

Hicas doesnt operate below about 80mph does it?

More trouble than it's worth IMO and I know I'll get slated for saying that but it's true!

 

Lock it off mate with a kit you can get from Courtesy or Phuong.

 

I'm seriously thinking about it...when I got some money! LOL :D

Honda invented it as far as I know, me Bro had it on his Prelude and it was ace.

 

However, on the Z it works slightly differently!

 

On the Honda you can see the back wheels move even when parking, on the Z? Nowt mate, it moves the back wheels fractions of degrees on cornering. I am no expert and would love right now for Nico to be here but to be honest and this is quoted from someone who has worked for Nissan for years! It does not alot for what it is! ;)

Not in agreement with Timmy here, (now there's a suprise), HICAS is a very good system IMHO, not as extream as the Honda System but in some ways far superior. It all just has to be in good condition.

 

TBH I'm not sure if the ECU controls it, I would assume yes, I think what you are perhaps getting confused with is the hydraulic and electronic versions of HICAS. Electronic being the later varient.

 

It is easy to tell which you have by looking under the bonnet and if there's a cylindrical component approximately 8-10" long at the front LHS in front of the PS resevoir then it's hydraulic.

 

I'll leave the control question open to the real tech heads. Sorry I couldn't be of more help.

 

Oh and btw, I'm not sure that Honda 'invented' it, from a quick scout around, I've found a 1956 US patent for a 4 wheel hydraulic steering aid. :D

 

Tim

HICAS works most of the time. Between 20 and 100mph

I belive it may need to just be in good condition. When i got my Zed the power steering pump was gone. Got that replaced along with a pipe that was leaking. The steering was better obviously. Anyway found there was a second pipe leaking. Got this done and now my car feels so, so much happier it's unreal. I do belive it's now on rails!!!!!!

Hey - I /like/ my HICAS... I think ;) I wouldn't mind having the option to turn it off simply to see how the car would handle without it. Must admit, after having a 4-wheel laser alignment check / reset done it handled way nicer.

 

Don't mean to be rude tho - my original question was about the ECU controlling the HICAS. Whether it's hydraulically or electrically operated something still has to make a decision about when it should operate.

 

Re-reading Henri's post tho (found in the archived stuff) he talks about how the HICAS system can't be disassembled like the ECU ROM. So I guess I'm kinda answering my own question. But does that mean it's a seperate box? So where is it? How quick can I pull it apart and start fiddling?! Lemme at it!

You can pull out the fuse to the HICAS to see what its like without, only problem is it disables the power steering too so it makes it rather heavy to turn!

LOL! Could make testing HICAS in a slalom, or round some nice tight bends quite hairy!

I understood that the HICAS control looks at car speed and the speed you rotate the steering wheel so that gentle correction type turns have a different effect to quick turns to miss an Elk standing in the road for instance.

 

The HICAS rack first turns the rear wheels in the opposite direction to the one you steered just for a very short time. This is similar I guess to a rally driver kicking the rear out before he turns into a bend. Once the HICAS has made the rear move the other way and started rotating the cars axis it then turns the rear wheels in the same direction as the front wheels and this means the car actually crabs slightly. All happens very fast. The whole result is the car should feel very chuckable and turn in sharply. If it feels all vague at the back then you probably have wear in one of the many joints or bushes.

 

I think the Honda system only turns the rears in the opposite direction to the fronts in a fixed ratio whatever speed and never changes phase. The HICAS system tries to be more clever and is commanded from an ecu.

 

The diagnostic in the manual is like a PS2 cheat with turning steering wheel from left to right 5 times tapping the brake pedal 5 times and so on with neutral selected etc. Read it yourself to check it properly! I was surprised to see you can have to bleed the rear power cylinder if you get air in the system - as in letting your fluid level get too low! Bet that would make it steer funny

 

Willie

the HICAS is explained in the manual, it works very little at low speeds and to a greater degree at high speeds. its really for high speed cornering i have been told, and yes! i can really feel the back end come round when doing a long sweeping corner at over a tonne. from what i can remember, and i may be wrong, is that the HICAS runs on its own system and does not talk to the chip.

 

steve

 

ps, i think the HICAS makes a great drive.