I am getting a code 14 and intermittent loss of power steering. I understand code 14 is speed sensor, my speedometer is working fine even when the power steering fails, could they be related? First thing I will do is clean the connectors on the speed sensor, what else can I do to diagnose?

 

Thanks, Dan

Have one probe at whatever pin it is from the cluster, and the other probe on the relevant pin at the ecu and then hicas control unit. Then see if it still beeps.

So from the clocks to pin 6 on the hicas unit?

Yeah, and do the same from the clocks to the ecu too, since you said it couldn't see the signal either.

From plug to plug it beeps. Cluster plug to plug pin 53 on ecu and cluster plug to plug pin 6 on hicas, both make a circuit ..

In that case, pass. :(

 

It'd be one hell of a coincidence if it does turn out to be both clusters with the exact same fault. Whereabouts are you? I'm in Harrogate if you fancy a road trip?

I might just do that, lol. I guess I need to try a set of clocks and a speed sender.

 

I have been for a drive and can confirm I can drive for quite some distance with no problem. Infact I believe I can drive with no issue at all as long as I don't slow down below 30ish mph. As soon as the car has gone above that speed it won't lighten the steering up after coming below that speed. Unless of course ignition off and back on..

The power steering will work at first, since it assumes you're parked, so just gives full assistance. But after a while it realises you aren't, and then goes into failsafe mode.

But like I say, I really wouldn't think it's the speed sensor itself at fault, since the speedo works.

As I understand it the circuit starts at the gearbox sensor, to the clocks, onto the ecu and hicas then onto where? Steering rack? Is it possible that if there is a fault on the rack sensor then it will shut the system down? Or should I still get a speed signal from the ecu regardless?

 

If it was your car where would you go from here?

 

thanks,

That's as I understand it too. From the sensor to the cluster, from the cluster to the various control units. The steering angle sensor has nothing to do with the speed sensor.

 

If it was mine, I'd do things the same as I've told you on here. Start with consult to see if there's a speed signal. In your case there isn't, yet the speedo works. So then I'd try checking for continuity from the clocks to the hicas control unit, which you have. I'd try another set of clocks, but again you have. So I don't know really, borrow someone else's hicas ecu to make sure it's not just the control unit at fault? I've got one sat in my car which is currently off the road if you wanted to try it.

Cheers bud, going put a thread up see if anyone's closer to home and see how I go on, but might just take you up on that. Thanks for all your help. :)

 

Dan

Let me know how you get on fella. :)

Ok, got a mate here with me now, we have gone through everything again, jacked the back of the car up in the garage and looked for signals at both the ecu and hicas units and am getting fluctuating voltage as the wheels are spinning. I am still getting code 14.

 

Only other thing is I recently swapped the ecu over and the fault has come about since then, the fault is still there however even if I swap back to my original ecu.

 

Obviously I don't know why the fault would still be there even if the ecu's are swapped (no stored code). Do any other modules store codes?

 

If an ecu is in kmph could that trigger a fault?

 

Thanks

No mate, the ecu doesn't dictate the measurement of speed, it simply interprets what it's told by the clocks.

Even if the speed signal was wrong, there's still a speed signal. All it would do is behave differently depending on what speed it thinks the car is travelling at.

Ok, I have now tried on my car a different set of clocks and a different hicas control unit. Neither fixed the issue.

 

I tried my ecu talk on the doner car and that car had no speed reading either. So I can only assume now that my software dosnt read speed signals from 300zx ecu's.

 

What comes after the ecu and hicas now? Sensor on the rack?

 

Thanks

Like I've said before, the steering angle sensor on the rack is nothing at all to do with the speed signal. If that was faulty, you'd have a hicas error code telling you so.

 

Surprised to hear that you couldn't get a speed signal on another car too though, what lead are you using? My offer still stands if you want me to have a look.

I am using a consult plug to a USB into my laptop, I am using ecutalk software. Where abouts exactly do you live?

 

Many thanks

Harrogate fella, north Yorkshire. Can't remember if you said before where you are or not.

Cheers, I'm in Stoke on trent, im going to have another look at it all this week.

 

Another clue though maybe. Today the car did a journey start to finish about 3 miles in all. Stop start at the beginning and upto about 45mph and the power steering worked right through. The return journey was back to heavy steering after a few hundred yards...

 

Thanks

Sorry I didn't mean angle sensor I meant the solenoid on the rack. I get a steady 5.5 volts when the steering is light and a steady 1.5 when it is heavy. But something isn't telling it to adjust again as the speed changes..

 

Thanks

Dan

That's due to the absence of a speed signal. The hicas control unit changes voltage to the power steering solenoid on the rack based on what speed the car is travelling. If it thinks it's parked, it supplies full assistance by opening the valve. The faster you go, the more closed it goes, restricting fluid flow through the rack. In your case, that isn't happening since there's no speed signal, so after a while it's dropping into failsafe mode, where it supplies barely any assistance since it'd be safer than full assistance while going at speed.

ok, i don't know if you can confirm for me, but the solenoid gets its signal from the hicas control unit, correct? That gets its signal from the ecu and that gets its signal from the clocks. I am down to this three items I guess. There's nothing else it could be?

 

many thanks,

It's either the clocks, ecu/hicas control unit, or the wiring. There's nothing else it can be, given your speedo actually works, suggesting the speed sensor is okay.

The only thing I'm not sure about is if the signal is split after the clocks and goes to both the ecu and hicas individually, or if it passes from one unit to the other. I've never had to find out, and my car is currently in the bodyshop so I can't confirm it for you. It's a shame you're now closer.