Abs Warnuing Light On

[Jemmo]

The ABS warning light has come on on my Avensis. The Toyota manual simply states to take the vehicle straight to a Toyota dealer. Is this necessary or could it just be the pads are worn and need replacing?

[Mops1]

Could be worth a try - I'm no expert and i'm sure others will correct me but have you checked to see if the sensor is dirty. I think it sits behind the wheels so attracts dust/dirt etc.

Fingers crossed it is something simple.

[Jemmo]

Could be worth a try - I'm no expert and i'm sure others will correct me but have you checked to see if the sensor is dirty. I think it sits behind the wheels so attracts dust/dirt etc.

Fingers crossed it is something simple.

Thanks - I'm going to check pads/shoes on the weekend, so I'll check/clean the sensor as well.

Might be worth bleeding the system as well as I have unequal rear braking apparently.

[hertsnminds]

As well as the wheel sensors and brake fluid you also have to check the hydraulic control unit (brake valve block) and the ABS ECU (computer) as these are the three main components in the ABS system.

[Jemmo]

As well as the wheel sensors and brake fluid you also have to check the hydraulic control unit (brake valve block) and the ABS ECU (computer) as these are the three main components in the ABS system.

And what do I do with the Hydraulic Control Unit? I'm looking at the Haynes manual and it doesn't say a fat lot about it. If it's the same thing as the 'hydraulic modulator' it tells you how to disconnect it, and that that it's 'a sealed precision assembly and must not under any circumstances be dismantled'. And of course, 'refitting is the reversal of the removal operations'.

Oh lawks, this could be comp-lic-ated!

[Jemmo]

Checked all the pads and shoes today and there is plenty of wear left so didn't change them - just cleaned out all the dust.

Tried to undo the sensor mounting bolt on the passenger side wheel and the bolt head sheared off. Brilliant!

After that I daredn't try and undo any other bolts in case the same thing happened.

So I didn't bleed the braking system, and I'm well cheesed off!

[hertsnminds]

it's 'a sealed precision assembly and must not under any circumstances be dismantled'.

Same as the ECU. Yes if you are an electronics engineer you could repair the ECU. If you are a hydraulics expert you could check the hydraulic modulator. But if you are in any doubt I would test the unit and replace as a whole if it is faulty.

[Jemmo]

Well the local garage couldn't get into the Toyota error codes so I had to take it to the nearest dealer.

Turned out to be corrosion on the plug from the sensor to the ECU and a broken wire.

They cleaned off the corrosion, and fixed the wire - £79.

Cheaper than having a new sensor fitted so am pretty pleased with that.