4WS Not working. Some debugging already done SOLVED

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sat Dec 16, 2017 5:10 pm

Yes, Good idea about unplugging sensors one-one to see what that throws up.

"Uneven sensors" sounds to me like either a mis-match between the sensor reading (one not responding or is giving a different/incompatible reading) or the timing is out of expected range, as you say.

For the first one, is it possible that the sensor wires are somehow crossed, so one of these sensors is reading in reverse direction?

For the second one, when you try to operate the steering, do you see the rear steering react at all? If so, does it look like it reacts more slowly than expected? Or like it's sticking/seizing? Is there any noise from the rear rack that suggests it is sticking (a squeak or scratching noise etc)

Scott560 · Post by **Scott560** » Sat Dec 16, 2017 5:25 pm

i got a spare 4ws ecu here i dont need. Probably even got the relay somewhere aswell. Let me know if you want it posting out - £5 delivered... fully working from when i broke my last lude.

And if you local to oxfordshire - i have a 4channel digital oscilloscope also if you want to check that the sensors are working like a rotary encoder. I havent looked much into the 4ws system but it definitely isn't happy when the voltage drops a bit low. My guess is the rack gets stiff with age (along with the ball joints/track rods, and the 4ws rack cannot push it to where its required and throws a code. I never bothered looking up the code as the reset always fixed it.

Scott560 · Post by **Scott560** » Sat Dec 16, 2017 5:26 pm

one way to test if it is friction in the assembly, is to jack the rear of the car off the ground, then start her up and actuate the steering after a reset. Without the car being on the ground the 4ws should be much easier to actuate and help rule in / rule out if its an issue (like i said, its the only time mine has ever come on).

Scott560 · Post by **Scott560** » Sat Dec 16, 2017 5:37 pm

one other thought is that the 4ws will need a fair amount if juice.

statically testing the voltage when there is no draw wont highlight any voltage crops as a result of load over a sub-standard feed. Worth checking the big fuses in the engine bay (none half gone, burnt out , cracked,coreded etc), and worth cleaning up the main feed under neath the car (be careful, its perm live i recall one user claiming).

Again could rule it out by running a fresh 12v feed with some beefy and well terminated wire as a temp solution (i havent seen it, but i believe it mounts onto the rear rack by screw terminal/post)

AeroNotix · Post by **AeroNotix** » Sun Dec 17, 2017 8:32 pm

Hi again.

I managed to get an oscilloscope on it. I connected the scope to the input of every sensor into the 4WS unit. The auxiliary sensors are just potential dividers, they don't provide any digital signals. When I attached the scope to the front sensor and turn the wheel, from left-to-right I get between 0.9v and 4.1v. This is what the diagnostics book says I need to have. Same for the rear auxiliary sensor.

I then attached the scope to phase A, phase B and phase Z of both the front and rear main sensor. The scope I was using only had two channels but you can see a video of the scope here: https://photos.app.goo.gl/MSPs9XNDqL0E94ev2 this is phase A and phase B together. You can see that the scope trace aligns with what the diagnostics book says. When I attached a channel to phase Z along with one of the other phases the trace looked correct.

I then managed to find a 4WS unit locally and fitted that, believing that this surely must be what I need to change. I changed that out, reset the error codes and still the 4WS was not working.

Right now I believe my only option is to find someone who has performed the neutral steering alignment to say yes or no as to whether I am performing it correctly.

wurlycorner wrote:Yes, Good idea about unplugging sensors one-one to see what that throws up.

"Uneven sensors" sounds to me like either a mis-match between the sensor reading (one not responding or is giving a different/incompatible reading) or the timing is out of expected range, as you say.

For the first one, is it possible that the sensor wires are somehow crossed, so one of these sensors is reading in reverse direction?

For the second one, when you try to operate the steering, do you see the rear steering react at all? If so, does it look like it reacts more slowly than expected? Or like it's sticking/seizing? Is there any noise from the rear rack that suggests it is sticking (a squeak or scratching noise etc)

Whenever I unplug a sensor I get a change in the error code. It goes from the error code which says the signal is incorrect to the error code which says it has no signal.

Remember that I have a second 4WS unit here. I am not fully mounting it but I am plugging it in and resetting it. Both units behave exactly the same. When I turn the wheel the unit tries to move a little bit with a smooth motion making no noises.

As of now I genuinely believe I am not performing the neutral alignment properly.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Sun Dec 17, 2017 9:52 pm

Yep agree. That's exactly what it sounds like, then.
Very impressed with the level of fault finding you've carried out.

Vtecmec is the process in the translated 5g manual, the same as on a 4g? Any tips?

Post by **Vtecmec** » Sun Dec 17, 2017 11:10 pm

When I did it in my 4th, calibrating the sensors to neutral involved rotating a sensor to line it up before locking it into place.

To tell if it was out to the left or right, I only had to decipher the flashing 4ws light on the dash. Too far out one way and the lights blinks in a prescribed way, informing which way it needs to be moved.

AeroNotix · Post by **AeroNotix** » Sun Dec 17, 2017 11:19 pm

Here's an issue I am having with setting the neutral position on a 5th gen.

Polish version: https://i.imgur.com/HtCLqjY.png

Translation follows:

Loosen the four mounting bolts mounting the rear 4WS unit and lower the unit (AeroNotix expansion: it's easier to get to the screws on the auxiliary sensor when you do this. It's not entirely required). Next, loosen the two screws mounting the auxiliary sensor to the 4WS unit.
Connect the SCS connector (AeroNotix: expansion, the blue two pin connector)
Turn on the ignition but do not run the engine. WARNING: The rear auxiliary angle sensor is ready for neutral alignment after four seconds
Release the handbrake
Slowly turn the rear auxiliary sensor left until the 4WS light turns on.
When the auxiliary sensor is out of alignment it will flash irregularly. Turn the sensor in place until the flashes become regular. Tighten the sensor when the flashes are regular.
Remount the 4WS unit.
Remove the SCS connector.

Now see the issue is, I cannot get it to light up when I turn the auxiliary rear sensor. I've even removed the sensor entirely and actuated the thing in my hand through its entire range and it will not light whatsoever throughout that range.

I've tested the sensor with a multimeter and, as mentioned, the auxiliary ones are potentiometers/potential dividers with three pins. E.g. the left two pins go low resistance while the right two pins go high resistance.

I have no idea why it's not lighting up. Am I stuck in a different "mode"? I.e. is it stuck waiting for me to do something else with a different part of the alignment?

AeroNotix · Post by **AeroNotix** » Sun Dec 17, 2017 11:22 pm

Vtecmec wrote:When I did it in my 4th, calibrating the sensors to neutral involved rotating a sensor to line it up before locking it into place.

To tell if it was out to the left or right, I only had to decipher the flashing 4ws light on the dash. Too far out one way and the lights blinks in a prescribed way, informing which way it needs to be moved.

Seems like the process is the same, only with a different kind of sensor. It's really frustrating!

This Prelude was supposed to be my winter beater a bit along with wanting to mess around with Hondas more thoroughly. My "main" car is an EP3 Type R which I want to keep in excellent nick, which it is. Right now since I got stuck into this it's outside in the snow in -5c. I feel sorry for it.

Scott560 · Post by **Scott560** » Mon Dec 18, 2017 2:19 pm

Here is a thought , to set the neutral on the rear , you must first assume the front is neutral/straight ahead?

Perhaps in the past, the wheel was refitted/alignment done whilst not straight ahead. Perhaps it is actually the front you must confirm is 'electronically' dead ahead first (regardless of what has been set via the track rod end adjustments/steering wheel position).

I read in one of your earlier posts a similar procedure for finding the dead ahead position for the front sensor - perhaps this needs to be done first before the light will work correctly for the rear adjustment?