Jump to content
SAU Community

R32 non hicas power steering solenoid issues!

D.phantom
 Share

Recommended Posts

D.phantom Newbie

D.phantom

Posted
Posted

So I’m having issues with my power steering. the obvious heavy and light and comes on and off randomly now it’s constantly heavy. I’ve read through forums regarding this issue and what I’ve gather is that it’s referring to hicas deletion. That’s the problem mine didn’t come with hicas. 
 

I’ve rebuilt the steering rack, pump, changed the bent hardline on the rack and taken out the solenoid to clean and loosen up the actuator, applied 12v to get it moving. Roughly checked the loom to see if there’s any damage to the loom and nothing.

Now I’m checking the wiring. I’ve tested the wiring to the solenoid and it’s fluctuating between 0.07v to 0.03v. Does anyone know what it’s supposed to be reading? 5v?

Anyone one know how this all works? Is there a fuse in between? What else is it connected to? How does it connect to the speed sensor? A resistor fried in the ecu? Please help. It’s been years

Thanks in advance 

GTSBoy Grand Master

GTSBoy

Posted
Posted

I have no idea what the power steering control module is on a non-HICAS car because I've never seen one. But it is a fair bet that is essentially the same thing as on any other Nissan of the period with variable PS. So, Maximas, that sort of thing.

It will pick up the ECU's speed signal off the "bus" (there's not really a bus - any consumers of the VSS are all just connected to that output on the ECU). The output should (most likely) be a PWM signal to give you an effective average voltage between the minimum and maximum values. You could possibly look at the HICAS part of the R32 manual to see what that range is likely to be (for non-HICAS, as it should be about the same).

joshuaho96 Veteran

joshuaho96

Posted
Posted (edited)
8 hours ago, D.phantom said:

So I’m having issues with my power steering. the obvious heavy and light and comes on and off randomly now it’s constantly heavy. I’ve read through forums regarding this issue and what I’ve gather is that it’s referring to hicas deletion. That’s the problem mine didn’t come with hicas. 
 

I’ve rebuilt the steering rack, pump, changed the bent hardline on the rack and taken out the solenoid to clean and loosen up the actuator, applied 12v to get it moving. Roughly checked the loom to see if there’s any damage to the loom and nothing.

Now I’m checking the wiring. I’ve tested the wiring to the solenoid and it’s fluctuating between 0.07v to 0.03v. Does anyone know what it’s supposed to be reading? 5v?

Anyone one know how this all works? Is there a fuse in between? What else is it connected to? How does it connect to the speed sensor? A resistor fried in the ecu? Please help. It’s been years

Thanks in advance 

I don't have the full R32 factory service manual so I don't really know how to help you here but there is an EPS control module that modulates the EPS solenoid, marked C or 28500 in this diagram.

 image.thumb.png.af6e1547292bee80e0f6d5d28d15cb25.png

The R32 GTR service manual floating around mentions it should be about 4.4-6.6V between the diagnostic connector and solenoid valve at 0 kph, then 1.5-2.2V at 60 mph, it also has the no HICAS equipped variant connector mentioned:

image.thumb.png.f1f12cce19a64ae324d6582517c35299.png

image.thumb.png.390825fb873add842c2333a3a399627b.pngimage.thumb.png.d6c32abacecb1a69277c022bdec22d2b.png

 

Edited by joshuaho96
  • Like 1
GTSBoy Grand Master

GTSBoy

Posted
Posted (edited)
2 hours ago, D.phantom said:

Do you know where the EPS module will be located?

image.thumb.png.fd78be733479c0946963fb0425c52e15.png

A is the HICAS CU.  As far as I know, there are no other modules located at A in a car with HICAS, so it is fair to presume that F is the variable power steer module for non-HICAS cars. Same location, give or take. Makes sense - the wiring loom for the HICAS cars has the speed signal, power, solenoid drive, etc wires all present there - so why move the module and have to upend the wiring loom?

 

Having said the above though, it may be the case that F is further down in the rear guard - it's hard to tell. In which case it may be something else.

2 hours ago, D.phantom said:

And also the diagnostic connect located under the dash?

Yes, it is the multi-pin plug next to the under dash fuse box. Top left corner. Can't miss it. Be very careful though - use insulated probes to poke around in there so  you don't accidentally short 12v to ground or an ECU input etc etc.

Edited by GTSBoy
joshuaho96 Veteran

joshuaho96

Posted
Posted (edited)
1 hour ago, GTSBoy said:

image.thumb.png.fd78be733479c0946963fb0425c52e15.png

A is the HICAS CU.  As far as I know, there are no other modules located at A in a car with HICAS, so it is fair to presume that F is the variable power steer module for non-HICAS cars. Same location, give or take. Makes sense - the wiring loom for the HICAS cars has the speed signal, power, solenoid drive, etc wires all present there - so why move the module and have to upend the wiring loom?

 

Having said the above though, it may be the case that F is further down in the rear guard - it's hard to tell. In which case it may be something else.

Yes, it is the multi-pin plug next to the under dash fuse box. Top left corner. Can't miss it. Be very careful though - use insulated probes to poke around in there so  you don't accidentally short 12v to ground or an ECU input etc etc.

I don't know if this is accurate. The EPC places the EPS control unit somewhere in the engine bay or somewhere in the interior near the firewall, presumably because the things it's controlling mostly live up in the front of the car unlike HICAS which has a whole steering rack on the rear axle to handle.

@D.phantom The R32 GTR manual actually has more than I give credit for talking about the non-HICAS cars:

Screenshot2024-05-05at11_09_51PM.thumb.png.873630d4a25ea9abdf967beea42b9d76.png

You can probe the pins on the diagnostic connector directly to read the EPS solenoid voltage as far as I can tell following the flow chart.

Edited by joshuaho96
GTSBoy Grand Master

GTSBoy

Posted
Posted
4 hours ago, joshuaho96 said:

The R32 GTR manual actually has more than I give credit for talking about the non-HICAS cars:

Nah. I reckon that that is the HICAS CU. Just the large plug, PS specific and other I/O. I can't see that there'd be a need/want for the (non-HICAS) PS CU to be watching any of those inputs other than the speed sensor.

joshuaho96 Veteran

joshuaho96

Posted
Posted
10 hours ago, GTSBoy said:

Nah. I reckon that that is the HICAS CU. Just the large plug, PS specific and other I/O. I can't see that there'd be a need/want for the (non-HICAS) PS CU to be watching any of those inputs other than the speed sensor.

Screenshot2024-05-06at2_13_37PM.thumb.png.c2c4aa46a34a8cf01c54f048d2d12c40.png

HICAS has a much more complicated circuit diagram, for some reason the R32 GTR service manual discusses both. The HICAS module has proper 2 way communication over consult, the "EPS control unit" doesn't have any of that and only exposes a raw analog voltage for the EPS solenoid valve. It's ultimately mostly about speed sensitive steering but the non-HICAS unit also looks at the neutral switch/brake/clutch switch to adjust how it provides assist.

GTSBoy Grand Master

GTSBoy

Posted
Posted
40 minutes ago, joshuaho96 said:

the "EPS control unit" doesn't have any of that and only exposes a raw analog voltage for the EPS solenoid valve. It's ultimately mostly about speed sensitive steering but the non-HICAS unit also looks at the neutral switch/brake/clutch switch to adjust how it provides assist.

Yeah, alright, I take it back. I hadn't bothered to compare the terminal numbers - they're not the same. I was working on the presumption that it was the "small plug" half of the HICAS CU because it has the same plug as the small plug on the HICAS CU. And...the drawing says "Refer to Super HICAS system circuit diagram" which seemed to place it firmly in the world of HICAS, not non-HICAS.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By GTSBoy · Posted

      My thinking is that if the O2 sensor is shot then your entire above described experience is pure placebo.
    • silviaz
      Steps to DIY sanding car back ready for respray....

      By silviaz · Posted

      Here is the mess that I made. That filler there was successful in filling dents in that area. But in the middle area. I can feel dents. And I've gone ocer it multiple times with filler. And the filler is no longer there because i accidently sanded it away. I've chased my tail on this job but this is something else lol. So I'm gonna attempt filler one more time and if it doesn't work I'll just high fill primer the door and see where the issues are because guidecoat is of no use atm.
    • silviaz
      Steps to DIY sanding car back ready for respray....

      By silviaz · Posted

      Ok, so I think I sort of figured out where I went wrong. So I definitely overthinked it, and I over sanded, which is probably a large part of the problem. to fix it, I ended up tapping some spots that were likely to be high, made them low, filled them in, and I tackled small sections at a time, and it feels a lot better.    I think what confused me as well is you have the bare metal, and some spots darker and some are lighter, and when I run my finger across it, it' would feel like it's a low spot, but I think it's just a transition in different texture from metal to body filler.    When your finger's sliding on the body filler, and crosses over to the bare metal, going back and forth, it feels like it's a low spot. So I kept putting filler there and sanding, but I think it was just a transition in texture, nothing to do with the low or high spot. But the panel's feels a lot better, and I'm just going to end up priming it, and then I'll block it after with guide coat.   Ended up wasting just about all of my filler on this damn door lol  
    • MBS206
      remote oil cooler hose size, 8,10 or an12?

      By MBS206 · Posted

      -10 is plenty for running to an oil cooler. When you look at oil feeds, like power steering feeds, they're much smaller, and then just a larger hose size to move volume in less pressure. No need for -12. Even on the race cars, like Duncans, and endurance cars, most of them are all running -10 and everything works perfectly fine, temps are under control, and there's no restrictions.
    • nouveau_poor
      Unknown sound similar to BOV on positive boost with partial throttle RB26

      By nouveau_poor · Posted

      Update: O2 sensor in my downpipe turned out to be faulty when I plugged in to the Haltech software. Was getting a "open circuit" warning. Tons of carbon buildup on it, probably from when I was running rich for a while before getting it corrected. Replaced with new unit and test drove again. The shuffle still happens, albeit far less now. I am not able to replicate it as reliably and it no longer happens at the same RPM levels as before. The only time I was able to hear it was in 5th going uphill and another time in 5th where there was no noticeable incline but applying more throttle first sped it up and then cleared it. Then once in 4th when I slightly lifted the throttle going over a bump but cleared right after. My understanding is that with the O2 sensor out, the ECU relies entirely on the MAP tune and isn't able to make its small adjustments based on the sensors reading. All in all, a big improvement, though not the silver bullet. Will try validating the actuators are set up correctly, and potentially setting up shop time to tune the boost controller on closed loop rather than the open loop it is set to now. Think if it's set up on closed loop to take the O2 reading, that should deal with these last bits. Will try to update again as I go. 
×
×
  • Create New...