info on abs speed sensor F/R

[neoeire]

hi all....
i have a 1990 rev 1 mr2 turbo,
my abs light is on and the error code indicates the front right or rear left sensor is faulty.

im guessing its the front right as the light came on after i recon'd the front calipers. i then pulled out the sensor thinking it wouldnt be that expencive to just replace it(how wrong i was at £200 odd notes lol)
so i got a hub with sensor for FR off a '90 rev1.

now my question, i plugged the sensor in to test its working before ripping the old hub off, did the 8 quick stamps on the brake pedel, andwatch the abs light go off with a big smile on my face....
then a few seconds later the abs light came back on...

does this mean that the replacement sensor is faulty?(best way to check this?) or could it be the rear left too?but dont see how as i didnt bother that wheel when it 1st came on...?
or even if testing it that way works at all?(cant see why not as the hub is self contained, no drive shaft through the middle)

any help would be great as i need to mot her...

[neoeire]

plus whats the difference between 1990 abs speed sensors off rev 1
and
1991+ rev2+ abs speed sensors...

they kinda looks the same in pictures iv seen... but they seem to be listed seperatly by years... ie 1990 and then 1991-99

[4ndee]

I'm sure there all the same. If it had fixed the fault the light would go out as soon as you start it you don't need to stamp the pedal. I would look at the wiring and the rear one.

[Peter Gidden]

Bit obvious for this time in the morning, but have you checked any of the sensors in any way?

[neoeire]

Bit obvious for this time in the morning, but have you checked any of the sensors in any way?

when the fault originally came up after i put the calipers on about a 7months ago, i checked to see what the fault code was, which indicated front right or rear left speed sensor was faulty, then had both wheels off checking them over...
and figured it was the front right as it was fine til i done the calipers on the front..

i did get instuction to check the sensor with a multi meter, but i did that some time ago now and cant remember the result but it seemed ok(ill check it again, and do the same for the rear left at the weekend).

main problem is im now living in essex and my baby is sitting in my mates drive in heathrow...


so basically, if the other sensors are ok? then connecting the replacement hubs wire to the system should knock the light off without me bolting the replacement hub on for testing purposes...? (unless this hub abs is faulty too?)

[Peter Gidden]

i did get instuction to check the sensor with a multi meter, but i did that some time ago now and cant remember the result but it seemed ok(ill check it again, and do the same for the rear left at the weekend).

so basically, if the other sensors are ok? then connecting the replacement hubs wire to the system should knock the light off without me bolting the replacement hub on for testing purposes...? (unless this hub abs is faulty too?)

There are two areas of testing from a sensor/hub point of view. First is sensor resistance. Easy to check as per BGB. The ECU will also check when ignition is switched on and if not correct throw it's toys out and illuminate the PAS light.

Then there is the reaction in the sensor caused by the rotation of the ABS ring. As the ring rotates, it will produce an AC waveform which the ECU monitiors so it knows each individual wheel speed. If the ECU does not receive a predicited response from each wheel within the first 500m (distance possibly not correct but it doesn't matter) it will again throw it's toys out and illuminate the PAS light. To check the response we use a 'scope whilst rotating the wheel.

[neoeire]

i did get instuction to check the sensor with a multi meter, but i did that some time ago now and cant remember the result but it seemed ok(ill check it again, and do the same for the rear left at the weekend).

so basically, if the other sensors are ok? then connecting the replacement hubs wire to the system should knock the light off without me bolting the replacement hub on for testing purposes...? (unless this hub abs is faulty too?)

There are two areas of testing from a sensor/hub point of view. First is sensor resistance. Easy to check as per BGB. The ECU will also check when ignition is switched on and if not correct throw it's toys out and illuminate the PAS light.

Then there is the reaction in the sensor caused by the rotation of the ABS ring. As the ring rotates, it will produce an AC waveform which the ECU monitiors so it knows each individual wheel speed. If the ECU does not receive a predicited response from each wheel within the first 500m (distance possibly not correct but it doesn't matter) it will again throw it's toys out and illuminate the PAS light. To check the response we use a 'scope whilst rotating the wheel.

whats BGB? and dont you mean the ABS red light? not PAS?(thats power assisted steering isnt it???)

ill didnt get the chance to go to west london this weekend, but ill be down there at some point during the week so im going to test the resistance with all the abs sensors and see what reading i get with the multimetre...

then see were i go from there... it could possible be that this replacement hub is dodgy as it looks a mess(wasnt to fond of the idea putting it on there)

[Peter Gidden]

whats BGB?

An acronym for Big Green Book - Toyota's OEM workshop manual.

and dont you mean the ABS red light? not PAS?

Yes, i meant the ABS light.

[neoeire]

o lol, yea i got that manual but in pdf lol

thanks for all ur help mate...