Say hello to my little friend!

[zem_41]

I have been reading up on the speed sensors, and I read somewhere that if the no2 one fails which I think mine has then the ecu can get a back up signal from the no1 sensor that runs the speedo? Is this the case with mine or are the two not linked?
Gonna pop to the scrappy and grab a sensor in a bit which I hope will work or it's off to toyota tnrw morn.

[BUSHWHACKER]

I have been reading up on the speed sensors, and I read somewhere that if the no2 one fails which I think mine has then the ecu can get a back up signal from the no1 sensor that runs the speedo? Is this the case with mine or are the two not linked?
Gonna pop to the scrappy and grab a sensor in a bit which I hope will work or it's off to toyota tnrw morn.

Jack the rear wheels off the ground and support truck with axle stands.
Attach the probes from your multi-meter to the two wires going to the speed sensor.
Put transmission in neutral, multi-meter to Ohms and turn the wheels or propshaft slowly by hand and see if the reading fluctuates.
If it does then the sensor is working.

At the original Surf ECU plug that gets left behind in the footwell (the plug that you connected the tacho signal wire to) there's a blue/green wire that goes to the speedo.
Switch on ignition and check that the voltage at that wire fluctuates when you turn the wheels. If it does, then there should be a thin yellow wire thats coiled up at the 28 pin Lexus ECU plug. connect this wire to the blue/green wire in the Surf plug. This is now the backup speed sensor signal.

Hope that makes sense.

[zem_41]

Yep makes perfect sense mate thanks, I have had the truck up on axle stands already and turned it in neutral and there's no fluctuation there at all so it must be the sensor :-( will try again bit later just to confirm though.
I remember you saying that if that speed sensor doesn't work then the truck won't get out of 1st but mine seems to do the opposite where it goes up the gears too quick.

[zem_41]

It seems to tick over at 250 rpm too or just below, is this normal? Doesn't cut out though

[zem_41]

Can't seem to find where we wired the fuel pump straight to the ignition?

[zem_41]

Just checked the speed sensor it seems ok, there's resistance there and as the prop is turned it jumps up in ohms.

[zem_41]

Checked the blue green wire which did have voltage on the prop turning so connected that up but still no change.
Would I need to reset ecu on adding that wire?
Thanks

[BUSHWHACKER]

It seems to tick over at 250 rpm too or just below, is this normal? Doesn't cut out though

It'll read low as the tacho is calibrated for a diesel engine. There is a potentiometer that can be adjusted, just turn it fully clockwise....

Can't seem to find where we wired the fuel pump straight to the ignition?

Yep, one of the thick black wires with the red or yellow stripe.

Just checked the speed sensor it seems ok, there's resistance there and as the prop is turned it jumps up in ohms.

OK, then it might be the ECU.
That one I gave you to get the truck running came from eBay and I don't know whether if it's a good one or not as I've never needed to use it.

Unplug the solenoids plug on the passenger side of the transmission and see if you get all gears by shifting the lever manually.

Did your LS400 have a kickdown switch under the throttle pedal?

[zem_41]

Reply

Reply

It'll read low as the tacho is calibrated for a diesel engine. There is a potentiometer that can be adjusted, just turn it fully clockwise....



Yep, one of the thick black wires with the red or yellow stripe.



OK, then it might be the ECU.
That one I gave you to get the truck running came from eBay and I don't know whether if it's a good one or not as I've never needed to use it.

Unplug the solenoids plug on the passenger side of the transmission and see if you get all gears by shifting the lever manually.
i can get the gears ok if I select them when driving? Is this what you mean?
Did your LS400 have a kickdown switch under the throttle pedal?im not 100% sure but I don't remember seeing it

the ATF level on idle doesn't register on the dip stick, but when it's hot and the engine is off it's half way up the hot mark

[zem_41]

Just got codes from ecu, so with te1 earthed and the ignition on
2 flashes
1 flash
2 flashes
7 flashes
2 flashes
8 flashes
2 flashes
9 flashes
7 flashes
1 flash
7 flashes
8 flashes
Pause
Then it repeats
Thanks

[BUSHWHACKER]

Replythe ATF level on idle doesn't register on the dip stick, but when it's hot and the engine is off it's half way up the hot mark

It needs topping up then if it's not registering with the engine idling.

The level should be halfway in the hot zone on a hot transmission, and halfway in the cold zone on a cold transmission.

The level will rise with the engine off as it's not being pumped around the transmission.

[BUSHWHACKER]

Just got codes from ecu, so with te1 earthed and the ignition on
2 flashes
1 flash
2 flashes
7 flashes
2 flashes
8 flashes
2 flashes
9 flashes
7 flashes
1 flash
7 flashes
8 flashes
Pause
Then it repeats
Thanks

So thats:
21
27
28
29
71
78

You can ignore codes; 27/29 (Sub O2 sensors) 71 (EGR) & 78 (Fuel pump control)

21 & 28 are main O2 sensors in the manifolds, have you plugged them in?
(That may be due to the different ECU)

[zem_41]

Yep all plugged in

[BUSHWHACKER]

Yep all plugged in

Could be due to the different ECU then.

Anyway, forget about them for the moment and get that ATF topped up.

[zem_41]

ATF fluid topped up
No change :-(