ABS sensor polarity?

[m17ch]

Hello,

I'm having issues with my ABS - after a short drive if I stab the brakes the abs light on the dash turns on and stays there until I restart the car.
I rewired the engine myself, which required the right ABS sensor (LHD car) to be rewired as well. I chopped the plug off the stock harness and completed the circuit to the F1 connector (under the dash) with a shielded cable, which shield I grounded to chassis (as per the FSM schematics). Nothing else was changed.

I double-checked the connections and the splices, all seems fine... could it be the polarity of the sensor, as I didn't pay attention to which wire goes where.
My thinking is that if the ABS unit sees off-phase signals from the two front wheels it might throw an error and fail-safe stop working...?

Anyone had the same issue?

[alanjuggler]

is this the original S13 system?

I had the exact same problem, again, after splicing the sensor connections. literally, a short drive, braking and then it'd come on and stay on. I had the polarity exactly the same, so couldn't explain it away that way.

I'm not much help for fixing it, I have a collection of ABS ecus that all delivered the same result (by the way, I have a stack of them spare, if you need), I ended up just getting my 180SX which is more like the S14 system and uses the more modern sensors.


https://www.sxoc.com/vbb/showthread....ors&highlight=

found the original thread. I thought I'd fixed it at points but it always ended up coming back. I suspect in the end it was wiring that was good enough for static testing but must have been breaking down under even the small signals an ABS system puts through.

[m17ch]

Indeed it is a standard euro s13 ABS system. It worked 100% with no issues before the rewiring, so it has to be something with it...

[alanjuggler]

yeah, that's what I thought with mine. I went completely and utterly bananas trying to figure it out. used sensors, pumps, ABS ecus, the lot. never worked again properly.

when you say you rewired it, was it with a crimped connector or soldered ?

[m17ch]

I couldn't find the pins for the ABS connector (male side), so I couldn't crimp the connector itself with the new wire. What I did was cut the original wires 5cm away from the connector (making a pigtail), and crimp the new wire to it.

[alanjuggler]

you may as well try switching the polarity to see if it works, it's easy enough to try. I know later Nissan's care about the polarity but that's where they used hall effect sensors instead of an inductive sensor.

have you disturbed anything else? the abs ring, done any work on the hubs or anything like that? definitely no flaky bits of iron/rust on the end?

[m17ch]

I swapped the polarity. It seems it fixed the problem... Not sure if it's due to polarity or better contact as I repinned the connector...
I guess one less gremlin ��

[alanjuggler]

glad it's worked