2G Few Nippondenso ABS Unit Questions

[knochgoon24]

I know you can ground the #1 pin on the OBD2 port to read the codes with the Bosch units, but is there some similar way to check codes on the Nippondenso units? I had to replace 2 wheel speed sensors due to damage, and my ABS still isn't working.

I'm getting the four flashes from the ABS ECU firing up when the key is turned to ON. I can't clear the light with the 10 brake pedal pulses either.

And if there isn't a way to read the codes, are the ABS computers interchangeable? I know of a few ABS equipped cars in my local junkyard. I could one of the Bosch ones and diagnose the problem with it if I really needed to.

 

[Kryndon]

Reviving this on purpose. Currently battling (again) with my constant ABS light ever since I've had the car (4 years). It's also a '97 facelift Talon but manufactured late '96, so it has the Nippon-Denso ABS ECU and a relay next to it, under the passenger kick panel.

Shorting the pins does not work, neither does ANY, and I mean ANY kind of scan tool, including MUT-2. I was reading the service manual and basically the way you test the system is by probing the harness-side connector pins (35 pins total), or by using a special connector tool which plugs into your ABS-ECU and you can probe the pins that way.

I don't have that tool and I doubt anybody else does either, so right now I got 2 spare Denso ECUs to check, and I will double check that my speed sensors/wires are intact. Because there's no way to communicate with the Denso ECU and thus easily obtain a code for what the problem might be, we have to literally check over ALL of the ABS related system and troubleshoot it that way.

If I get any results I will post here.

 

[Kryndon]

Turns out I had the rear right ABS sensor wire broken in the area where it sits sandwiched between the rear subframe and chassis. Ended up running a new cable. Now all my sensor test out at 1600 ohms, which is more than the factory service manual lists (1000-1200 ohms), but if they all measure the same, it means they do work. They could simply have been replaced or whatever.

Anyway, after fixing the wire, the ABS light stayed on. So I swapped in two other known good Denso ECUs, but again, the light stayed permanently on. It doesn't even blink, it's just on as soon as you turn the ignition to ON. Shorting the pins doesn't produce a code, and neither does the 10 brake pedal presses.

What sucks is that even if you know ALL of your ABS system is in good order, as long as you have the light on, the system wont work. This is what happens when your car was manufactured in the exact transition period from all-mechanical to all-electrical canbus systems...


EDIT: So my dumb ass apparently forgot that I had taken out the main 50 amp ABS fuse a long time ago... Put that sum bi*** back in its place, ABS light IS FINALLY OFF!!!! 4 Years with this goddamn light and finally I managed to fix the issue. And all it was was a broken abs cable (damn rodents).

Things I learned: Always test your sensor wires first! Either at the ABS-ECU connector under the passenger kick panel, or at least for the rear sensors, at the fuel pump hanger. And if you get a permanent ABS light that doesn't flicker or blink, it means you either have no ABS fuse or the fuse is popped. Hope this helps anybody with a '95-'96 ABS car!

 

[DJRace]

Turns out I had the rear right ABS sensor wire broken in the area where it sits sandwiched between the rear subframe and chassis. Ended up running a new cable. Now all my sensor test out at 1600 ohms, which is more than the factory service manual lists (1000-1200 ohms), but if they all measure the same, it means they do work. They could simply have been replaced or whatever.

Anyway, after fixing the wire, the ABS light stayed on. So I swapped in two other known good Denso ECUs, but again, the light stayed permanently on. It doesn't even blink, it's just on as soon as you turn the ignition to ON. Shorting the pins doesn't produce a code, and neither does the 10 brake pedal presses.

What sucks is that even if you know ALL of your ABS system is in good order, as long as you have the light on, the system wont work. This is what happens when your car was manufactured in the exact transition period from all-mechanical to all-electrical canbus systems...


EDIT: So my dumb ass apparently forgot that I had taken out the main 50 amp ABS fuse a long time ago... Put that sum bi*** back in its place, ABS light IS FINALLY OFF!!!! 4 Years with this goddamn light and finally I managed to fix the issue. And all it was was a broken abs cable (damn rodents).

Things I learned: Always test your sensor wires first! Either at the ABS-ECU connector under the passenger kick panel, or at least for the rear sensors, at the fuel pump hanger. And if you get a permanent ABS light that doesn't flicker or blink, it means you either have no ABS fuse or the fuse is popped. Hope this helps anybody with a '95-'96 ABS car!

That is almost funny that it was simple as that. Glad you got it figured. Thanks for the good info for us with ABS problems!