1UZ ECU Identity + Code 47

[GreyBeard]

It does seem strange (that i'm seeing code 47) if it is the case that a disconnected plug does not generate a code.
I'll work on it some more with all the extra info
thanks

[manny]

Does the ECU pin orientation match this diagram?

[CrUZida]

Looks like an 89-92 Celsior ECU to me.

I think I've got the same one in my Supra (will confirm later), but it has never thrown code 47.
I've left the sub-throttle sensor unplugged too.

[GreyBeard]

reset ecu
pluged in the sub tps
drive, all clear
stop
start, drive
now getting code 42 (VSS)
code 47 gone


reset ecu
removed sub tps
drive, all clear
stop
start, drive
code 42 (VSS)
code 47 still gone

have not had code 42 before today

1 step forward, 1 step back. or maybe 1 step sideways?

[CrUZida]

42 - speed sensor - is the input from the DASH to the ECU.

Not really required for a manual, and I believe the light will only turn on with speeds over 100kph.

It *may* assist the ecu with the idle circuit (ie, slowing down for traffic lights), and I'm not sure if it affects the cruise fuel mixture, but that would be about it.

Lots of people don't bother hooking it up (it controls the 180kph speed cut), and no one really reports any issues.

[GreyBeard]

it's auto
don't know why code 42 has appeared
there has been no discernablle change in driving/running/shifting with either error

[CrUZida]

Oh, auto.

There are 2 speed sensors, which is why it still shifts fine.

One goes direct from gbox to ecu (this one would still be working)
One goes from dash speedo to ecu (this one throws code 42)

If your speedo stops working, code 42 will happen.
If your speedo is working, and the SPD wire is wired up, then the output from the dash may have stopped working.

[GreyBeard]

wtf signal is the ecu expecting to see from the speedo? I have (working) VDO speedo running off the speed sensor on gearbox.

is there actually 2x speed sensors or is the ecu just wanting to flirt with the speedo for some unnecessary reason?

[jzk25]

There are two speed sensors, a reluctor that goes straight to the ECU and a 3 wire hall sensor that goes to the dash and then back to the ecu. With the Aristo ecu(same setup) you can just wire up the power and earth and run the signal staright to the ecu.

I agree that it looks like an 89 celsior ecu too. I had issues with rev cutting in park setting strange codes on a HX ute I did a celsior driveline into, I believe it is an ecu fault though.

Did you say the CEL is flashing? Or is the OD light flashing? Either way, you'll probably never get either to stay off all the time and it doesn't seem to make any difference to the performance or economy of the engine.
One thing I noted with the Ute was that it needed a kickdown switch or the auto would not work properly.

[CrUZida]

Kickdown switch is def not required.

It takes a lot of effort to even activate the switch in a Celsior.
(its a very stiff button and needs a fair amount of pressure).

[Sciflyer]

heh, same in the early UZZ31 i have, seemed odd

they got rid of it in the '94+ ones

[GreyBeard]

still got the code 42
It's the O/D light that flashes and displays the codes
Coz I'm a perfectionist, it irritates me that it's coding even though I cannot detect any effect on engine/driving/shifting. It will go on the back burner for now.
Ecu wiring will be changed later in the year with gas install so I'll have to resist the temptation fiddle with it until then.

[CrUZida]

If its the O/D light that flashes then its the 2 wire sensor on the rear of the gbox.

The sensor has either become unplugged, failed, or the wires have failed.

[GreyBeard]

If its the O/D light that flashes then its the 2 wire sensor on the rear of the gbox.

The sensor has either become unplugged, failed, or the wires have failed.

that's speed sensor #2?

O/D flashes when vehicle is running indicating some error
O/D displays the various actual codes when ecu is in dignostic mode

[CrUZida]

Yes, yes and yes.

The car is still shifting because the primary sensor (SPD/SP1, from the speedo) is still working.

Unplug the speedo and you'll see the box do wierd things.