Every second Skyline listing in the country mentions HICAS, usually as “HICAS locked”, as though that settles something. It does not. Whether you should service the rear steer, lock it or bin it entirely comes down to what the car is for, which generation of the system you have got, and how much you enjoy conversations with warrant inspectors.
What HICAS Is Actually Doing Back There
A Degree Of Rear Steer, And Why Nissan Bothered
HICAS – High Capacity Actively Controlled Steering – steers the rear wheels. Not much: about a degree either side of centre, and only when the car decides it is worth doing. The ECU watches road speed, steering angle and how fast you are winding the wheel on, then nudges rear toe to suit.
At motorway speeds it points the rears the same way as the fronts. That flattens the initial yaw, so a lane change feels like the whole car moved at once instead of the nose leading and the tail arriving late. Some versions briefly toe the rears the other way at lower speeds to sharpen turn-in, then settle back in phase.
Nissan was chasing stability in a heavy, powerful, rear-drive coupe. On a healthy car it works quietly enough that nobody thinks about it, which is the problem when it stops being healthy.
Hydraulic On The R32, Electric By The R34
The chassis code matters more here than most people expect. R32 HICAS is hydraulic – a small rack on the rear subframe, fed with pressure from the power steering circuit, with solenoids doing the deciding. That means hard lines running the length of the car, a rack with its own seals, and fluid nobody has touched since the car was in Japan.
The R33 sits in the middle. Still hydraulic, but with sharper electronic control, and badged Super HICAS.
By the R34 the whole thing had gone electric. A motor-driven actuator moves the toe links, there are no rear hydraulic lines to leak, and the system talks to the rest of the car over the loom. The failure lists are not remotely the same: an R32 seeps and goes soggy, an R34 throws a code.
Why It Goes Vague With Age
Most cars here with weird rear-steer behaviour do not have a broken ECU. They have thirty-year-old rubber.
The rack sits on bushes, the toe links have their own, and the subframe rests on four more. Every one has been quietly turning to biscuit since the car landed. Add a rack that seeps, tired lines and fluid the colour of tea, and the rear toe starts moving when the ECU never asked it to.
The symptom is a car that feels like it is steering itself slightly on a bumpy back road – a small lag, then a correction you did not make. HICAS gets the blame. Half the time it is the bushes, and a pry bar and a torch will tell you that before you spend a cent on delete parts.
The Three Honest Options
Service It And Leave It Alone
This is the option nobody brings up at a meet, and it is often the right one. If the car is a road car, the rack is dry and the bushes are the only real problem, a rear bush refresh puts the handling back to roughly how it left the factory – which, for a road car, was pretty good.
Budget around $150 to $300 for a decent set covering the rack mounts and toe links, plus an alignment afterwards, because you have just changed the rear toe whether you meant to or not. Add a few hours if the subframe bolts have never been out.
Keeping a working system also keeps the car standard, the dash clean, and the warrant conversation short.
The Lock Bar Middle Ground
A lock bar replaces the rear HICAS rack with a solid, fixed-length bar so the rear toe cannot move at all. It is the most common answer in this country for good reason: a decent bar runs $150 to $350, it bolts to the existing rack mounting points, and it is an afternoon’s work.
What gets forgotten is that the bar is only half the job. Pull the rack out of an R32 or R33 and you still have live hydraulic lines that need looping or blanking properly, not capping with whatever was in the drawer. On an R34 the mechanical side is easier but the loom is not, because the actuator is gone and the car knows it.
Buy a bar that has actually been engineered. Box section someone welded up in a shed is still a steering component holding your rear toe, and a certifier will treat it as one.
Full Delete, Pump And All
A proper delete goes further than bolting a bar in and walking away. Done fully it means:
– rear rack out, engineered lock bar in, on unmodified factory mounts
– hydraulic lines removed rather than looped and forgotten, on the R32 and R33
– the HICAS pump deleted or bypassed with a delete pulley and the correct belt
– the electrical side tidied at the fuse box and ECU rather than left dangling
The payoff is a rear end with nothing left to fail, a few kilos gone, one less fluid to service, and a car that behaves the same on lap three as it did on lap one. That repeatability is the real reason track cars get deleted, not the weight.
The cost is time, and accepting that you have modified the steering system on a road-registered car – which is where the paperwork starts.
The Bits That Bite You Later
What Actually Changes In The Corner
The handling change is smaller than the forum arguments suggest, and it does not all go one way.
With the rear locked, turn-in at speed feels a fraction lazier, because nothing is helping rotate the car. Motorway lane changes want a touch more input at the wheel. In return, the rear does the same thing every single time, which matters enormously once you are near the limit and reading the car through your hands rather than your eyes.
On the road, a healthy HICAS car and a well sorted locked car are closer than anyone admits. On a track day, the locked car is easier to trust. If you cannot decide, drive both – there are enough of each in the NZ scene that someone at a Sunday meet will hand you the keys.
Warning Lamps And The Warrant
Lock or delete the system without sorting the electrical side and the HICAS warning lamp comes on. That is not a cosmetic annoyance.
An illuminated steering system warning lamp is a fail item at warrant time, and rightly so. The inspector has no way of knowing whether it is reporting your lock bar or a genuine fault in a system that steers the car.
The wrong answer, and it gets suggested constantly, is making the lamp go away without making the fault go away. Pulling the bulb, taping over the cluster or wiring in a resistor purely so the light stays off is defeating a warning device on a steering system. Do not do it, on any chassis, for any reason.
The right answer is a delete done properly, so there is no fault left to report, and telling the inspector what has been done.
Where The Certifier Comes In
Plenty of owners assume HICAS removal is settled ground. It is not, and the answer depends on how the work was done.
Changes to a vehicle’s steering system are exactly the category the low volume vehicle scheme exists to cover, and low volume vehicle certification is the pathway if your inspector or certifier decides your car needs it. A bolt-in bar from a known manufacturer, on untouched factory mounting points, is a far shorter conversation than fabricated brackets or a subframe someone has been at with a grinder.
The practical move is to ring an LVV certifier before you order parts, not after the car has failed a warrant. Ten minutes on the phone tells you what your chassis, your bar and your inspector will want to see.
HICAS is not a bolt-on to be undone on principle. It is a steering system Nissan spent real money developing, and on most of these cars it works fine right up until the rubber holding it together gives up. Decide on the car in front of you and what the alignment sheet says, not on what the bloke at the last meet did to his.