ABS issue with JZA70 using MA70 bits

[JZA70R_92]

Hello Guys

I’ve converted my MA70 automatic to 1JZGTE 5sp R154 Using full JZA70 engine bay, interior looms. the MA70 had abs brakes so I obtained the correct rear speed sensor and dissected the abs wiring out of the MA70 looms. I’ve left the NL, PL wires disconnected and for the BATT wire that goes to ECU B I’ve wired that to dome fuse 12 VOLT also the 2 white/black stripe wires which are ground I’ve attached that to chassis ground. just wanted to clarify if that is ok. At this stage I turn on car and ABS light turns on then goes off after 3 seconds. Problem is I drive down the road and after 50 meters the light comes on and won’t go away. ive got the TSRM for diagnostic testing but wanted to know if the way I wired it is good enough for it to work! FOR TESTING
Ive also noticed even though the 1JZ didnt have abs it still has the rear sensor wires part of the engine loom that connected in the engine bay that goes to the white plug under d
See attachment

FROM MA70 ABS COMPUER

NL = Disconnected as related to AUTO stuff
PL = Disconnected as related to AUTO stuff
+B = Wired to 1JZGTE ECU +B
BATT = Wired to Dome fuse wire Blue/yellow. ON ma70 it went to ECU B fuse also Blue yellow wire
ECT = Disconnected as related to AUTO stuff
STP = Wired to Stop light wire Green White that also goes through M1 Connector
PKB = Wired to Black wire on hand brake

Rest of wires have been left attached to each other when dissected from ma70 looms so they plug correctly to ABS solenoid under bonnet

Im hoping peeweee sees this as I know he did this with his UZA70

[CrUZida]

Pull the codes from the ABS ecu, otherwise you'll just be chasing your tail

[JZA70R_92]

cool andrew but is the way I wired it up ok? ill post up a pic of the differance between factory MA70 and my way

[AndyTTR]

It sounds like it's wired up good enough for the diagnostics to work. Do what cruzida said.

If it faults after driving off then it's probably a speed sensor issue or plausibility error (eg. looking for a speed signal from the auto box to correlate with the wheel speeds / it's thinking the gear is in Park while you're moving... or something like that).

Diagnostics will tell you which one and where to start looking.

[JZA70R_92]

I have attached how i wired it up

[AndyTTR]

Pics are really small dude?

[JZA70R_92]

ok fixed I hope

[CrUZida]

There is a big plug just under/next to the ABS servo, unplug that and the system will go into diagnostics. (its a 2 pin from memory, big round long thing)

Without knowing what the fault is you'd be wasting your time.


All I did on my old UZA70 was wire in a rear speed sensor on the gearbox, after I got those pinouts right, she worked (or, at least she stopped complaining!)

[JZA70R_92]

ok ive wired it up correctly had to solder a length of wires to the sensor and a plug. it works ok at any speed under 10kmh as soon as i get past that and travel about 30 meteres dash light comes on. its code 33 rear speed sensor that is plugged fine arghhhh

[JZA70R_92]

by the way ive left the ECT wire disconnected as no auto box.

[AndyTTR]

The light comes on over 10km/h as that's when the computer probably does it's system check.

I'm not down with the A70, does it have 1 speed sender on the back of the gearbox to give the rear wheel speed signal, or does it have sensors at the wheels? Are you using the same gearbox and diff that were in the car originally?

[JZA70R_92]

only 1 sensor for the back on the gearbox. car used to be a MA70 auto abs. abs computer and its loom have been disected and transplanted back. the abs computer has this one wire thats blue yellow stripe marked ECT dont know if that could cause an issue as in the diagrams above it seems to be attached to the rear sensor

[AndyTTR]

Cool cool. More questions!

Are you using the original Auto diff still? Is its ratio a lot different to the manual diff ratio?

Did the sensor on the auto box have a 4-pin plug, and the new one only have 3-pins?

Has anyone done this gearbox conversion before and gotten the ABS to work?

Do you know if the A70 had different ABS ECUs for 7M / 1JZ / Auto / Manual?

[JZA70R_92]

hmmmmmm. the orignal auto diff is in there origianl sensor only has 3 pins aswell. dont if anyone has. well i thought it would work as I recall peewee running a w58 in his UZA70 and I thing it was factory auto aswell......

you could be on to something andy hmmm......

[AndyTTR]

Is it the same sensor in both boxes?

If it was only a 3 pin plug, where did that ECT wire actually go? In that diagram is says it should go to 'pin 2' of the sensor? Are you sure that plug you found actually goes to the speed sensor?

I suppose to help narrow it down you could stick the multimeter on the ECU pin that's supposed to get the rear speed signal and see if it is actually getting a signal while you drive (would be easier if you had a portable oscilloscope ). If there's no signal at all, then double check your connections...

If it is getting a signal, then it would probably be down to the rear signal not correlating to the front wheel speed signal (ie. front speeds consistently a lot faster / slower than rear speed due to gear ratios = error). It'd have to be a pretty big difference between the expected signal and the actual signal though...

If Cruz got it to work though... sorry I can't be of much help, don't have any experience with A70s.