c5 esr abs fault

[danny_c5]

Hoping for some help with a niggling issue on my c5

Abs, esr, esp system error messages and lights on the dash.

Front passenger side abs sensor replacement today and calipar on the side wheel.

Error has continued and brake pedal is bouncing until the esr message appears and then brakes goto normal and funcatkon as they should.

Had anyone got any suggestions as to what could be causing these messages and warning lights?

Cheers

[GiveMeABreak]

That’ll be a bit hard to diagnose remotely, you’ll need to get a proper diagnostic on it to find out what it’s not happy about. Did you have these errors before you changed the ABS sensor and the calliper?

[danny_c5]

Hi Marc

Yep, same problems prior to replacement parts today.
From a previous post last year Paul read the codes and it threw up the abs sensor but only just got round to replacing.
Problem being mot due next week so its going to be off the road until I can get them read and fixed.

Not a happy chappy today!

[wheeler]

Can you remember what the exact code was though? did it say the sensor was open circuit or that the speed information was missing/not plausible?
Normally if a sensor is dead it just disables the ABS system altogether.
If its a speed information/signal fault it suggests that the speed info is wrong rather than missing. I would get it on live data & you will probably find the speed on that wheel is all over the place so it thinks its skidding & activating the ABS. A sensor fault normally just gives a fixed silly speed of something like 255 kph.
I would start by looking at the magnetic pickup track on the wheel bearing, they can over time build up metal swarf/dust on the magnetic track causing erratic readings. The tracks are also easily damaged so check for ant signs of damage on the track. Be very careful when cleaning them, use some brake cleaner & a soft cloth.
A worn wheel bearing itself can also cause the ABS light to come on & a wheel speed fault if there is any freeplay in it, I would imagine though if the fault had been there since last year the wheel bearing would probably have collapsed by now.

[GiveMeABreak]

Also check that the tyres are the same on the front axle and the rear axle - different tyres / wheel sizes have been known to upset the ESP system too.

[Sloppysod]

Also check that the tyres are the same on the front axle and the rear axle - different tyres / wheel sizes have been known to upset the ESP system too.

Not just "different tyres" but different MAKES of tyre as well, unlike modern cars the X7 use the tyre rolling diameter to calculate wheel speed, my car had a Michelin or one side a cheap make on the other. After I placing a tape measure around the outside of the wheel/tyre, there was about 15mm difference, this was enough to make the car think is was skidding which resulted in my auto gearbox not changing up when straightening up from a leaving a round about. I swapped the 'cheap' with a bald Michelin and my problem went away.

[GiveMeABreak]

Yes, I never have mixed makes on the same axle - not recommended at all as it can also affect the stopping dynamics with the different tread patterns - quite correct Stu.

[danny_c5]

Update on the fault re ABS and ESP.

Had the car looked at this morning and two issues that have been identified.

Front NS wheel bearing pick up ring spilt.

Front NS over CV gaiter split.

Anyone got any ideas of how big a job this?

Cheers

[RichardW]

Need to replace the bearing if the track is wrecked - the bearings are not cheap (you want to fit an SKF bearing). I would think a garage would do both jobs in about 2 hours, plus parts, so you're looking at about £250 all in I would think. If you've got a decent tool kit you can do it yourself, and either buy a threaded puller, or get someone to press the bearing out/in, which will reduce it to under £100 and 3-4 hours DIY work.

[danny_c5]

Quick update on the abs esp issue.

Car done today, abs and esp light off, now time to get the mot booked in.

Mechanic has said that the suspension has a weep on both sides and advised to jet wash and dry these prior to mot. This was also an advisory on the mot last year. Suspension still seems to function as normal and the ride is fine. Is this something to worry about and are these expensive parts?

Unsure what this part is called but I was show the metal arm that where the suspension raises and lowers.

Cheers

[GiveMeABreak]

It's perfectly normal for these to 'weep' or 'mist' a little. The struts have a LDS suspension return pipe that just allows excess fluid to return under low pressure to the tank. To fail, there has to be a drip drip type of leak that makes small pool of fluid: Here's an extract from the official MOT guidance:

8.4 Other environmental items
8.4.1 Fluid leaks
You must check for fluid leaks on all vehicles other than Class 3. You should do this with the engine idling.

A leak of fluids such as engine coolant, screen wash and fluid required for Selective Catalyst Reduction aren't reasons for failure. You should fail a vehicle if a fluid leak creates a pool on the floor within 5 minutes that's more than 75mm in diameter or if there are many leaks which collectively leak fluid at the same rate.

You can refuse to carry out the test if there's an excessive fluid leak. For details see item 4 in the 'Introduction' of this inspection manual.

Defect: Fluid

• leaking excessively and likely to harm the environment or to pose a safety risk to other road users - Major
• leaking continuously and likely to pose a serious risk to road safety - Dangerous

[danny_c5]

Cheers Marc

Defo no pools of fluid.

Jet wash and a wipe and hopefully be fine