Light will come on after about 3-5 min of hwy travel. Light will not come on if driving in town. Light will not come on if driving hard on a twisty rd, with speed ranging 20kmh - 100+ Can NOT get into HICAS Diagnostic Occasionaly the spedo cuts out for a split second, often a few times within a 3-5 second period than run smoothly Help?, I want to know what part to get before the Z goes in to the Mech on tue.
Most likely the steering sensor.......>> If you can get anyone near you with a ConZult unit with HICAS diagnostics to plug in they should be able to tell you the answer. With the exception of the speedo occasionally cutting out your symptoms exactly match mine, and it was my steering angle sensor that was dead.
would you happen to know the part number? also can you remember the price?. and thanks for the help!! :thumbsup:
Could be speed sensor Most often speed sensor failure is caused by a plastic cog breaking up -my symptoms were the same as yours when this occured.
Is there a diagram somewhere of the speed sensor and its components, I would like to understand it better as my speedo intermittedly cuts out completely, and then leaves the power steering to go very hard (as if it isn't working at all!)
Does the steering angle sensor for the hicas => have to be at the bottom of the steering wheel when the wheels are straight??
It needs to be in its......>> "Home" position, in other words at zero degrees, or the car will think it is constantly turning a corner. After a certain number of kilometers the ecu will decide that no road in the world has a corner that long and deduce that the HICAS system is faulty. That is when the light comes on.
I'm going from memory......>> And will probably be wrong since it has been a while since I played with a steering angle sensor, but this is what I remmember. It can only be mounted one way, as the holes are spaced differently top to bottom. The problem is where the disk sits in relation to the sensor as the disk has a home position. If you look at it closely you will notice a heap of little slots cut around the outer edge. These slots line up with an optical sensor which effectively "looks" through them. At a particular point on the disk there is an extra slot which is the home position, and it is this that needs to be lined up with the sensor when the steering wheel is mounted and the car is traveling in a straight line. The sensor can then read how many degrees left or right the wheel has been moved from the home position by the sensor effectively "counting" the number of slots that pass befor it. Lining this up should be standard on the stock Zed wheel, but may be out on some aftermarket wheels. If you pull your steering wheel off and have a look behind it all of this will make a lot more sense.
Yes it does As stated a failed speed sensor caused a HICAS error in my car earlier this year, this was fixed by replacing a plastic cog somewhere in the assembly -Speed sensor fault was daignosed and repaired at UAS so it's not like you're taking my word for it
Well yours would be the first.........>> Of all the cars that have had failed speed sensors yours is the first I've heard with the HICAS light coming on. I'd love to know that it was with your fault that triggered the light.
Pete >> Not sure how they are related, but about 8 months ago I had a problem with, what I thought was my Instrument Cluster. Speedo would work intermittently, on & off, within seconds the Hicas light would come on & the steering would become heavy. Pulled the Cluster out & changed the diode to the speedo, as this seems to be a common problem, so I'm told. Still the same problem. :angry: Bought a new Speed Sensor & put it in. Hey presto!! Speedo works fine & the Hicas light doesn't come on anymore & the steerings fine, not heavy. :thumbsup: So my conclusion is, that these two are connected in some way, the Hicas & the Speedo. There must be a sensor somewhere that tells the Hicas when the Speedo fails in some way. :unsure: Cheers Kerry
Very interesting.........>> Yours Kerry is now the second one. There is obviously some link, but why isn't it happening to everyone who has a speed sensor problem? Perhaps it only happens if the fault is with the actual sensor itself? and if the problem is one of dry joints on the speedo then that doesn't turn on the light. I still believe Plasmos problem is likely caused by a faulty steering angle sensor due to the fact that his light comes on even when the speedo is working fine, but it does open up other possibilities.
Z-Car91 put me >> on the path when I described the symtoms that I was experiencing. John's an Electrical Engineer & may be able to explain the relationship between the two far better than me, but there definately is a connection there somewhere. Cheers Kerry
Looking at the service manual a failed speed sensor --> should throw a code and light the hicas light. As Pete pointed out, the wheel neutral position being out is the most common fault though. As shown in the below service manual images. Maybe an intermittent sensor doesn't always throw a code? :wacko:
Since HICAS is only active over a certain speed........>> If the fault with the speed sensor was such that the car "thought" it never went above that speed then presumably the light would not be triggered.. Also, since NAs don't have HICAS it would also explain why a large percentage of faulty speed sensors havent been see as HICAS fault lights.
I have an idea as to why this might happen The signal from the speed sensor travels to the instrument cluster and then onto the speedometer circuit board. Once it gets there it goes though some electrical components on the board before the signal is split. One side of the signal goes to the ECU while on the other side of the signal is modified agian via many electronic components on the PCB so it's able to drive the speedo needle. Therefore, if you have a faulty speedo due to a fault on the PCB which occurs after the signal split it will not affect the HICAS. This is the most likely scenario since the signal which goes to the ECU only passes though a few components on the speedo PCB and the odds of a dry joint occuring there are much less. Anyway, that is how it works on my instrument cluster which is a little different from the earlier models.
