Upgraded the callipers + discs on my mk5 fiesta zetec-s with with fiesta ST150 items on the weekend. The parts are a straight swap, but when I went for a drive afterwards the abs + traction control lights came on for about 1/4 mile then went off again. Why would this happen? They work absolutely fine.
I didn't touch any sensors or connections, didn't have to use any force on anything, I was very careful.

 

Has the light come back on since? Maybe just a bit of dirt or something got disturbed around the sensor.

 

Not used it since weekend, hopefully it was something like that. I don't understand how it works? I don't think there was any electrical connections on the hub like on a newer car.

 

Strange. I had no problems when I fitted bigger brakes on my old puma. Did you have the ignition switched on and did you spin the front wheels when you had the car jacked up.

 

The lights went off and stayed off when I first drove it, I just want to be certain it will be ok as I have a long drive across Europe next month it so it needs to be spot on.

ignition was off, I jacked one side of the car at a time, but now you mention spinning the wheels, it was parked in gear but as I lifted one wheel off it did turn a bit and make a bit off a clunk noise from the gearbox. I thought nothing of it at the time, could that of caused any harm?

 

There is a hall effect sensor on each hub, which inputs to a ABS ECU. Under normal conditions, they all give a similar reading.

However, when wheels are about to lock (as a result of hard braking) there would be a discrepancy and the ABS then activates.

This rapidly apply the brakes, giving the effect of cadence braking, which allows the vehicle to steer and brake simultaneously.

As Rich says, I suspect the sensor is the issue here.

ESC (i.e. traction control) also uses them as an input.

Martin

 

No, it's only the same difference as them being on the ground.

Martin

 

Just been out, lights are back on again. I've had wheels off and had a good look, I can see sensors and there's no way I have touched them while doing the upgrade. although I admit it must be related to what I have done.
is it best to get it checked with diagnostic equipment? As there's no way of really telling what's wrong is there?
is there anything I can do to narrow it down?

 

How did you bleed the new calipers? Could it be possible that air has got into the abs pump? I would be getting it scanned for codes, you should be able to read the abs module from the OBD port.

 

I didn't even think of that, is that a possibility? I just bled it with my Mrs, so might be worth me doing it again. I just assumed that was ok as the pedal feels good.
yea it has obd2 which I'm surprised about as its a y reg.
thanks for your help

 

Air is an issue if you let the reservoir run dry, but you would have spongy brakes etc.

Maybe there was a bit of dirt got onto one of the rings and it's now ok.

Martin

 

We'll, traction control and abs lights are on permanently now, I didn't even know it had reaction control, there's no on/off button for it.

 

Get the fault codes read, it will pinpoint the fault.

 

I will try and borrow a decent reader this week, I've just got cheap one.
the car was perfect last august when I put it away in the garage, since i got it out last week and I've changed the brakes I've got this issue, the screen wash bottle is leaking somewhere and I've just gone to use it now and it won't fucking start 😐 brilliant isn't it.

 

The sensors resistance can easily be checked on the respective ECU pins.

Martin

 

Looked at with a decent code reader, anyone elaborate on this?

 

 

Without sounding dumb, I assume the right hand side is the drivers side?

 

It is most likely the sensor on the drivers side. Could be coincidence, or you may have unknowingly pulled on the cable or something. You can take the sensor out and test it but you may as well replace it as they are cheap enough, I bought a cheap Chinese special off eBay a few years ago and it worked fine. If the sensor doesn't fix it then I'd be checking for continuity through the loom back to the control module.

 

Ok I will give it a try, seen replacement sensors on eBay for Ł8, cheers chap

 

I'd check the loom behind the arch liner for any broken wires first.

 

Drivers side sensor changed and jobs a good'n!

 

Result....