[Mk2] [Generic] Rev 5 ABS, this should not be possible...?

[2tmike]

My abs doesn't work, in that I can lock up either of the front wheels. The abs light functions normally and there is absolutely no sign of any mods to the wiring behind the dash. There are no current error codes stored. I've swapped the abs pump, both relays and the ecu all with no effect. No idea what to try next ?

[Baker]

Check abs sensors.
They're quite fragile.

[2tmike]

Wouldn't they throw a fault code?

[2tmike]

Sensors check out OK.
I'm coming to the conclusion that it might be air in the abs pump/valve module. Does anyone have a specific bleed method for this ? Some newer systems need to be hooked up to dealer equipment and the pump and valves cycled as part of the bleed process but I don't know about the MR2 system

[Rogue]

Check that the ABS ECU is receiving the STOP signal when you put your foot on the brake. If the ECU doesn't know that you're applying the brakes then it won't actuate the ABS solenoids - this is how I make the ABS switchable in MR2 Roadster race cars, which use a very similar system.

(Also check your brake lights work - same circuit!)

[2tmike]

Brake lights fully functional....same circuit as abs 'stop' ?
Mike

[Dame]

Does the car make the ABS buzzing noise as you start to pull off? It's a difficult noise to describe but very distinctive. If you're not sure maybe try pulling the fuse and see if any noises are absent when you pull off.

[Ste2]

Does the car make the ABS buzzing noise as you start to pull off? It's a difficult noise to describe but very distinctive. If you're not sure maybe try pulling the fuse and see if any noises are absent when you pull off.

would have thought the buzzing noise was the power steering pump - although happy to be proved wrong

[Ste2]

Does the car make the ABS buzzing noise as you start to pull off? It's a difficult noise to describe but very distinctive. If you're not sure maybe try pulling the fuse and see if any noises are absent when you pull off.

would have thought the buzzing noise was the power steering pump - although happy to be proved wrong

[Dame]

Nope it's definitely the ABS if we're talking about the same buzzing noise of course . I know this because when I had a faulty sensor wire moving it around made the noise happen intermittently as the circuit was reconnected. The power steering pump is up and running long before. I think it's a self test, it's a one off noise, hard to describe not really a buzz makes a sound a bit like "wow".

[2tmike]

The power steering pump noise I know well but have never heard the abs pump noise on the beams or, for that matter on the tubby where the abs does work.
The reason I'm thinking air in the pump is that in the last session of bleeding we had a hard pedal, then suddenly we lost it and when we re-bled the front drivers side a lot of very very tiny airbubbles came out. The fluid was almost milky in appearance but when it settled in the jar you could see the air coming out of it over a few minutes. I assumed that it had come from the pump and maybe the pump had been cavitating.
Silly question, but where are fuses for the abs system ?