Braking issues

[Andy GM]

Hi guys , just wonder if any of you have had a similar issue to the one my Z3 is currently having ,, every now and then (very randomly) my brake pedal feels like a crunching sensation but will then clear itself , I can only assume it’s linked to the ABS , I have ordered a code reader to try and shed some light but was after any of your experiences similar to this ,, thanks in advance for any advice

 

[Stevo7682]

Sounds like abs pump kicking in ( does it happen more often at slower speeds) if so probably an abs sensor about to fail .
Code reader should hopefully point out the exact fault.
What age and model is your zed .

Stephen.

 

[Andy GM]

Hi Stephen , thanks for your response , it’s a 2000 Xreg 3.0i ,, it’s very intermittent so hopefully a code reader will bring up the info ,, also sounds a little strange but (I’m hoping it’s linked as it seems to happen at the same time) its as though it has a temporary loss of power / acceleration when you lift your foot off the brake to try and rectify it !!! - very strange indeed!!!

 

[Stevo7682]

Reason asking some code reader struggle with reading abs control units on early zeds.
Did you also purchase the 16 to 20 pin obd cable as you will need this your obd2 port under steering only gives limited diagnostic access.
You need to use the round 20 pin sockets in engine bay

Stephen.

 

[Andy GM]

I didn’t order one of those but I will do now

 

[Stevo7682]

Easy to get on ebay you will need it for full diagnostic system access

 

[Andy GM]

That’s where I’ve just ordered one from mate , hopefully it will give me a definitive answer ,thank you for the help

 

[Stevo7682]

Best of luck .
Another thing I just thought of what does your zed have ASC or DSC

 

[Andy GM]

Funny you should ask but it’s got DSC and after I’d turned it off the car seemed to perform trouble free

 

[Stevo7682]

Back to probably faulty sensor.
Other potential issue for dsc equipped cars is water ingress to the yaw sensor located on the floor under the passenger seat ( and carpet) .
You can get an idea if all is well there if you lift the passenger seat motor to upper position get your hand under the seat ( if you look between outer seat and sill you will see where front and rear carpets join) under seat that join extends across the car you can get your hand in between the join and feel underside of carpets ( foam padding) to make sure it's dry.
Zeds can hide litres of water under the carpets and top stays dry.

 

[Andy GM]

I will definitely check it out although I’ve had the car for 18months and never had it out in the rain , that said I suppose it could’ve got in from when I’ve washed it , certainly will get checked though just to confirm that it is dry

 

[137699]

Check the castellated ABS reluctor rings - if they're split/damaged/rusty they can give the sensor erroneous readings which cause the ABS to kick in.

 

[Andy GM]

Check the castellated ABS reluctor rings - if they're split/damaged/rusty they can give the sensor erroneous readings which cause the ABS to kick in.

Yes I must admit the wheels are coming off this weekend (got pneumonia at the minute so not been able to do it over the last weekend) but I did think that the relict or rings might be the cause of the issue

 

[t-tony]

Another thing with the relcutor rings is that corrosion can build under them and that reduces the air gap to the Hall effect pick up (sensor) This mostly affects the rear sensors for some reason.
2 ways of curing this,1 is new drive shaft(s), 2 is remove the sensor (if you’re lucky) and place a thin washer between the sensor and hub where the fixing screw goes.

Tony.

 

[Andy GM]

Thank you Tony , it’ll be getting stripped at the weekend (health depending) and hopefully all will become apparent , thank you again for the advice and help

 

[t-tony]

Good luck on getting it sorted Andy. Keep us posted please.

Tony.

 

[Richard29]

I had same on my e91. Albeit a load of warning lights came on too. It was a wheel speed sensor. About £20 for the part and easy fit.

 

[Andy GM]

I had same on my e91. Albeit a load of warning lights came on too. It was a wheel speed sensor. About £20 for the part and easy fit.

Sorry for the late reply , I’ve had both front hubs in bits (callipers off , discs off etc) cleaned everything up and still seems to be doing it ,, plugged my code reader in and it came up with 2 faults (both relating to oxygen sensors) but soon cleared after the car had warmed up - possibly going to replace the abs pump as I have a new one in the garage and il see if that cures it

 

[Stevo7682]

There was no abs fault codes?.
If you change the pump it may require coding in to properly work.

This is the abs pump module off a early face-lift model with ASC ( mine ) well replacement I purchased to get to bottom of abs fault when I bought my zed.
On the asc equipped face-lift model the model separates from the hydraulic part ( no need to split open hydraulics) multiplug off then 4 inverted torque bits to remove it you could drive car without module as no effect on basic hydraulic operation just additional electronic aid won't won't and lights on dashboard.
Anyway getting off track here .
When you change my module the new one appears to work correctly but doesn't.
When turn ignition on and start abs and traction control lights come on and off as they should if you push the traction control button the light comes on dash then if you push again goes back out again.
But what you will find in reality the abs will be fully functioning but the traction control will not be ( only appears to be by light operating) the only way to sort this is to get the new module coded to vehicle so I am going to assume yours may be similar.
But changing it may still help get to the bottom of the issue.

Stephen.

 

[Andy GM]

The speed sensors for the front end have been ordered , il change those first to see if that’s the issue before I start dismantling ABS pump ,, very annoying as it’s something and nothing but not planning on getting rid of the car so it’ll get done one way or the other