Prado 95 ABS not working

[jordan_sorabjee]

So I have put in a tested ECU, still the same issue. I have also checked the 4WD ECU and that is fine. Does any of your vehicles ABS light up when diff lock is engaged? Mine does, thought it would though if its working.

Next step i need to test the earth and the live, I pressume I would do both by using the Volt settings on a multi meter not resistance. Is that correct? Any advice on this would be much appreciated.

 

[jordan_sorabjee]

Also I have checked the fusible link in the engine compartment and there is power going through it. Are there any other fuses in the system?

 

[Beastrider]

Hi - if you have the rear difflock engaged, then the ABS light should come on anyway - ABS is disabled when the rear diff is locked. (I thought Prado’s didn’t have a rear difflock, but had an LSD instead).

I listed out other fuses in my previous post, but just from looking through the wiring diagrams.

You can check the earth connections easily by disconnecting the ECU and checking continuity of the earth wire(s) back to a known good earth. Also check earth connection to the ABS actuator motor.
I am less clear about how to test all the other feeds from the sensors/relay/actuator.

 

[jordan_sorabjee]

Mine has a rear diff lock fortunately but no ABS light on activation. I have checked every fuse on the vehicle and can't find anything wrong.

Ill have a play with the earth wire tomorrow and see what I find. Thanks again.

 

[jordan_sorabjee]

I am thoroughly stumped. ABS ECU tested, checked all the live inputs to the ECU and the actuator, check all the earths, even actuated the ABS pump manually to check it works. Checked the brake pedal switch. Chedked the link connector.. Still the ABS does not work and no warning light.

If the ABS relay switch was damaged this should still bring up an ABS light, but ill replace it anyway. Is there any way to check the deceleration sensor?

Given that the ABS Light only comes on with the key turned to on, and never at any other time, could somebody have just wired it up to something else to pass a road worthiness test? How can I check if this is the case?

 

[Beastrider]

Equally stumped!
I can’t think of anything else to check.
I believe decel sensors can be checked by raising the rear of the car but you’ll need to search on google about what to procedure to do.
If the ABS light has been wired to something else, I suppose you’d have to carefully watch which other light comes on and goes off at precisely the same time as the ABS.
Wish I could help you further.

 

[jordan_sorabjee]

No probs. You have been a massive help already.

I am not sure what else to do. Managed to find a cheap second hand relay and decel sensor online so I'll try those. Also coincidentally changing the front calipers and servicing the rear. Always had spongy brakes on the car, maybe the stopping forces in the decel sensor have never been enough to activate the ABS. Not quite giving up...but pretty close. Thanks again.

 

[jordan_sorabjee]

SOLVED!!! Sort of at least. The ABS warning light in the dash had been bridged to another disused light on the dash, presumably as a dodgy fix by a local mechanic...TIA!

Now getting Error 31 and 32. Just need to work out what they are and get them fixed...

 

[Beastrider]

Hi - good to know you’re making progress and found something. There is old thread on here ‘ABS light stays on’, which includes a link to a YouTube video. That shows codes 31 and 32 relate to the ABS sensor cable malfunction (31 is the right front, 32 is the left front).

For reading the ABS codes, did you have to remove the short pin and then connect TC and E1 (just out of interest to know if you did it the same as in the video)?

 

[jordan_sorabjee]

Awesome. On close inspection I can actually see the front sensor cables are damaged around the control arm mounting point. I think this may be our problem.

With the fault code I connected Tc and E1 and then removed the short pin, turned to on and it gave me my codes. I see that you can search for addition code by adding an additional connection to Ts and driving in a straight line.

 

[Beastrider]

Hopefully, it’s ‘just’ the cables and re-routing the warning light. Will you try a repair to the cables? Genuine cables are about £150 each although pattern ones are about £50 each.

 

[jordan_sorabjee]

I've found some partern ones for £35 each so will start with those. While I'm waiting for them to arrive i am going to try repair the current ones. They have broken in an awkward place though. I have a replacement injector pump arriving tomorrow as well so that's the priority for this week. Sadly the SCV and TCV on the pump are very much on their last legs.

 

[jordan_sorabjee]

Boom! New wheel speed sensors arrived (£35 each made by Kavo). Fitted them this morning. The ABS light has finally gone out!

 

[Beastrider]

Hi - excellent news and thanks for the update - an important safety feature restored.

You mentioned earlier about spongey brakes. Remember to bleed through the rear load sensing valve as well as all calipers (rear calipers first). Book says Dot 3 but many owners are using Dot 4 or Dot 5.1 without problems, including me. Also check the rear calipers are sliding freely on their pins.

 

[jordan_sorabjee]

Brakes feel a tonne better since servicing the rear calipers. I adjusted the LSPV as well and that seems to have helped a lot. All in all, I think i have set of brakes that actually do what they are supposed to!