R32 power steering Light/heavy

[Rb25orange]

Hey everyone I know this has been discussed many times in past. I have gone through most of write up in regards to solving this.

So my steering goes light to heavy after 1min or so of starting to drive.
Little background — My hicas is deleted other than the wiring and HCU, i.e rear Hicas pump, lines, rack is deleted and fitted with lock bar in rear. 
That said, I have checked everything wiring related and it is all hooked up— other than below,
 

Questions ?

Will not having a steering angle sensor (behind steering wheel) cause this ?

Is there a pin on the ecu talking to hicas ? If yes which pin ?

I am aware pin 53 is speed wire from speedo, which is getting feed from speedo in my case. 
 

HCU itself seems to be working as if I disconnect it, my steering goes heavy from the start. It seems something is causing it to go in fail safe mode.

I don’t have hicas light on dash so haven’t done the self diagnose yet. 
Also does the nissan consult port gives you hicas related codes precisely ?

I am in located in Brisbane if anyone can help with the consult tool or point in direction which doesn’t cost kidneys.

looking forward to hear from you absolute legends out there 😘

[GTSBoy]

On 12/10/2021 at 4:08 PM, Rb25orange said:

Will not having a steering angle sensor (behind steering wheel) cause this ?

No, but you should need to have the smaller of the 2 plugs in the HCU pulled out to avoid the absent sensor (and the absent all the rest of it!) causing the HICAS system to go into fault and raise the dash light.

On 12/10/2021 at 4:08 PM, Rb25orange said:

Is there a pin on the ecu talking to hicas ? If yes which pin ?

Not that I know of. Break out the new scan of the wiring diagram that I posted up a couple of months ago and trace every wire from the HCU, just to be sure.

On 12/10/2021 at 4:08 PM, Rb25orange said:

Also does the nissan consult port gives you hicas related codes precisely ?

Yes, with a proper workshop grade diagnostics handset. None of the Nissan ECU code pullers will talk to the other CUs on the bus.

The HICAS CU definitely controls the power steering solenoid. The 25+ year old age of these cars has meant that the looming death of these CUs has been hanging over our heads wrt keeping the PS working properly.

The solenoid just gets a PWM voltage signal to vary the assistance, mostly with speed. It should be possible to fudge something up with an Arduino when we get desperate.

[GTSBoy]

Also, it could be the solenoid crapping out. Could have a bad connection in/on it that gets hot and gives up, or something more weird. Try putting 6V or so on it directly and see if you get consistent operation.

[Rb25orange]

On 11/12/2021 at 12:17 PM, GTSBoy said:

Also, it could be the solenoid crapping out. Could have a bad connection in/on it that gets hot and gives up, or something more weird. Try putting 6V or so on it directly and see if you get consistent operation.

While I do this temporarily to know working of my ps solenoid, should I just disconnect both plugs at the HCU ?

 

On 11/12/2021 at 12:16 PM, GTSBoy said:

On 10/12/2021 at 6:08 PM, Rb25orange said:

 

Yes, with a proper workshop grade diagnostics handset. None of the Nissan ECU code pullers will talk to the other CUs on the bus.

Can you please put a link to it here, I saw it when you first posted it. Can’t find it now.

 

[joshuaho96]

On 12/10/2021 at 6:16 PM, GTSBoy said:

No, but you should need to have the smaller of the 2 plugs in the HCU pulled out to avoid the absent sensor (and the absent all the rest of it!) causing the HICAS system to go into fault and raise the dash light.

Not that I know of. Break out the new scan of the wiring diagram that I posted up a couple of months ago and trace every wire from the HCU, just to be sure.

Yes, with a proper workshop grade diagnostics handset. None of the Nissan ECU code pullers will talk to the other CUs on the bus.

The HICAS CU definitely controls the power steering solenoid. The 25+ year old age of these cars has meant that the looming death of these CUs has been hanging over our heads wrt keeping the PS working properly.

The solenoid just gets a PWM voltage signal to vary the assistance, mostly with speed. It should be possible to fudge something up with an Arduino when we get desperate.

Nissan Datascan will pull HICAS codes and allow you to run HICAS active test. I plan on running that instead of whatever this magic Konami code thing is: https://www.importavehicle.com/blog/hicas-four-wheel-steering-self-diagnosis-procedure

[Rb25orange]

@GTSBoy

Also out of curiosity, do you know what will be the effects of deleting the solenoid off the rack and getting steering shop to blank it ? 
In that case its just running off the SP and hicas can be completely taken out of the story, but has only done this before ?

Also pin 19( PS idle up ). Is it linked to the pressure switch on lines going to rack ? Is it there just to tell the ecu to rev a bit on full locks ?

[joshuaho96]

On 12/10/2021 at 8:37 PM, Rb25orange said:

@GTSBoy

Also out of curiosity, do you know what will be the effects of deleting the solenoid off the rack and getting steering shop to blank it ? 
In that case its just running off the SP and hicas can be completely taken out of the story, but has only done this before ?

Also pin 19( PS idle up ). Is it linked to the pressure switch on lines going to rack ? Is it there just to tell the ecu to rev a bit on full locks ?

Regarding PS idle up that is the purpose yes. When the power steering pump pressure spikes because of full lock or low speed maneuvering it will drag the idle down otherwise so the signal is there to tell the ECU to bump the AAC duty cycle significantly. One of the few things Nissan did right was making that system electronic, on a lot of similar era Toyotas it's a purely mechanical valve and it's notorious for failing with age at which point your intake starts sucking a lot of power steering fluid.

Edited December 11, 2021 by joshuaho96

[Rb25orange]

On 11/12/2021 at 5:32 PM, joshuaho96 said:

Regarding PS idle up that is the purpose yes. When the power steering pump pressure spikes because of full lock or low speed maneuvering it will drag the idle down otherwise so the signal is there to tell the ECU to bump the AAC duty cycle significantly. One of the few things Nissan did right was making that system electronic, on a lot of similar era Toyotas it's a purely mechanical valve and it's notorious for failing with age at which point your intake starts sucking a lot of power steering fluid.

Appreciate that info man, definitely helps sorting some other issues I have been having with idle dropping coming to stop.

Atleast I am clear that switch is not bothering my hicas. 
 

I will be doing continuity test for my hicas wiring over the weekend, and update.

thanks

 

[GTSBoy]

On 12/11/2021 at 12:37 PM, Rb25orange said:

Also out of curiosity, do you know what will be the effects of deleting the solenoid off the rack and getting steering shop to blank it ? 

Very very heavy steering. You need at least some (minimum) voltage on that solenoid to gain assistance. I think a flat voltage would probably feel bad. That's why I'm leaning towards an Arduino type solution for those that need to replace the HICAS CU's duty.

On 12/11/2021 at 12:04 PM, Rb25orange said:

Can you please put a link to it here, I saw it when you first posted it. Can’t find it now.

I'm not sure what you mean by this. I don't have one. My bro-in-law is a machanic and has such a unit so I've plugged that in in the past to interrogate the steadily decreasing list of other CUs in my car (TCU is gone, HICAS is now neutered, ABS?TCS has been shaken loose from the NEO ECU's grasp).

You can use Strap-On brand, or any of dozens of other workshop grade diagnostic scanners. Just can't afford to buy your own - have to borrow.

[GTSBoy]

On 12/11/2021 at 12:04 PM, Rb25orange said:

Can you please put a link to it here, I saw it when you first posted it. Can’t find it now.

Oh, was your quote of my post messed up? In which case, were you asking for a link to my post with the workshop manual scan? Um.....I dunno, hold on while I look....

here

 

[Rb25orange]

On 12/12/2021 at 4:09 PM, GTSBoy said:

I'm not sure what you mean by this. I don't have one. My bro-in-law is a machanic and has such a unit so I've plugged that in in the past to interrogate the steadily decreasing list of other CUs in my car (TCU is gone, HICAS is now neutered, ABS?TCS has been shaken loose from the NEO ECU's grasp).

You can use Strap-On brand, or any of dozens of other workshop grade diagnostic scanners. Just can't afford to buy your own - have to borrow.

Sorry for my confusing jargo man, Yes I meant the link to the diagram/from previous post of u’s.

Definitely can’t afford one atm, I have my whole rear subframe stripped atm, so thought I will bell out all the wiring for the hicas while at it. 
 

Have checked my speedo wiring and sensor that all ticks out but I am yet to check pwm at speed signal going to pin53 to be 💯. 
 

thanks, much appreciate your help.

 

 

[joshuaho96]

On 12/11/2021 at 10:09 PM, GTSBoy said:

Very very heavy steering. You need at least some (minimum) voltage on that solenoid to gain assistance. I think a flat voltage would probably feel bad. That's why I'm leaning towards an Arduino type solution for those that need to replace the HICAS CU's duty.

I'm not sure what you mean by this. I don't have one. My bro-in-law is a machanic and has such a unit so I've plugged that in in the past to interrogate the steadily decreasing list of other CUs in my car (TCU is gone, HICAS is now neutered, ABS?TCS has been shaken loose from the NEO ECU's grasp).

You can use Strap-On brand, or any of dozens of other workshop grade diagnostic scanners. Just can't afford to buy your own - have to borrow.

There's no need for an expensive diagnostic unit to check for codes/active test the HICAS system. Nissan Datascan and a PLMS Consult cable will do great if you have an old laptop lying around somewhere:

[TXSquirrel]

Does this flow chart describe your issues?  Where your steering became heavy after a few minutes of driving, but it returned to being light after you restart?  This came off the gtr manual, not sure if it applies to others but hopefully it helps.

 

[Rb25orange]

On 18/12/2021 at 4:52 AM, TXSquirrel said:

Does this flow chart describe your issues?  Where your steering became heavy after a few minutes of driving, but it returned to being light after you restart?  This came off the gtr manual, not sure if it applies to others but hopefully it helps.

 

That definitely helps man, not to sure though how to test if speed signal from speedo is getting to the ecu (pin53). I am sure a normal multimeter doesn’t have a option to see pwm signals. I guess I need one that measures pwm signal and check at the wire to pin53. 

however on previous diagnoses I know the sensor is in place behind the speedo and wire from there to pin53 is continuous. 
 

@GTSBoy Input please, correct me if wrong, also is there a way to see speed signal at the wire to pin53 to see if the signal is generated at all ?

Also from previous conversation, I wanted to know how is the ecu talking to hicas, as the only wire I could find out goes from hicas to ecu. So how does hicas know what assistance is needed if signal from speedo is going straight to ecu and from there to where ? With the diagram I have I can pin8 at the bigger connector of 2 on hicas is controlling the steering rack solenoid, but not sure as said how is hicas getting this

 

 

info ?

 

[GTSBoy]

I haven't looked at the wiring diagram that closely, but I think the speed signal is available at the HICAS CU also.

As to how to "see" the speed signal....with a consult unit you can see what the ECU thinks the speed signal is. If you want to look directly, then you need to tap the wire with a CRO. You can buy cheap CROs that are USB or wifi these days that you can use with your computer or phone. Worth having.

[Rb25orange]

On 07/01/2022 at 9:49 AM, GTSBoy said:

I haven't looked at the wiring diagram that closely, but I think the speed signal is available at the HICAS CU also.

As to how to "see" the speed signal....with a consult unit you can see what the ECU thinks the speed signal is. If you want to look directly, then you need to tap the wire with a CRO. You can buy cheap CROs that are USB or wifi these days that you can use with your computer or phone. Worth having.

🖤

[TXSquirrel]

Looks like pin 5 is the speed input to HICAS.  Were you getting signal there?  Honestly I don't know what type of signal you should expect at pin 5.

[GTSBoy]

On 1/7/2022 at 9:56 PM, TXSquirrel said:

Honestly I don't know what type of signal you should expect at pin 5.

It's PWM 0-5v square wave. Same as the ECU sees from the cluster.

[Rb25orange]

But the question is what pin at the ecu is this coming from ?
In my case I will need to know this pin on ecu from 33gtst as its 25swaped and currently running stock ecu.  
But answer to both comp will help people rectify the issue in future.

 

[Rb25orange]

On 18/12/2021 at 4:52 AM, TXSquirrel said:

Does this flow chart describe your issues?  Where your steering became heavy after a few minutes of driving, but it returned to being light after you restart?  This came off the gtr manual, not sure if it applies to others but hopefully it helps.

 

Yes it does, it concludes my issue is PS solenoid related, my solenoid itself is working though as I wired it yo 6v for time being and it is working but do want to fix it properly as its light all times and doing sharp turns on higher speed (60-70) it feels out of control and tried 4v it feels weird at that level. So yeaa would be nice fixing it properly. Specially when I know it can be done.