R56 : ABS, DSC, TPM lights

[silentbrown]

Daughter's R56 Cooper has thrown up the dreaded yellow trifecta of dash lights. Code showing in Carista is 5D8F

Fault immediately reapppears when reset.

Just before this, it noted 'tyre pressure loss' (which I'd put down to the cold weather), so my first guess was an ABS speed sensor. I replaced front drivers side - no difference - then swapped over the passenger side one with the one from the drivers side - again, no difference.

I'm probably beyond my paygrade and don't want to randomly throw more parts at it. Any suggestions for a decent Mini specialist in the Hereford area?

[E-bmw]

So when you saw "tyre pressure loss" did you think about checking the pressures?

If so what pressure did you use?

What size wheels/tyres are they?

[E-bmw]

silentbrown said:

my first guess was an ABS speed sensor. I replaced front drivers side - no difference - then swapped over the passenger side one with the one from the drivers side - again, no difference.

I'm probably beyond my paygrade and don't want to randomly throw more parts at it. Any suggestions for a decent Mini specialist in the Hereford area?

So why did you "randomly throw those parts" at it?

[silentbrown]

E-bmw said:

So when you saw "tyre pressure loss" did you think about checking the pressures?

Yes, first thing I did.

E-bmw said:

If so what pressure did you use?

What size wheels/tyres are they?

Original wheels, Kumho runflats. 35psi (yes thats, ~5psi lower than factory recommended as the ride is hard enough to remove fillings on our local pothole-infested roads. It's tolerable at 35)

(Given it's an indirect TPM system I'm not sure why you think that's relevant?)

E-bmw said:

So why did you "randomly throw those parts" at it?

Well,quite: We've had ABS sensors fail on two other cars in the last couple of years. Identical symptoms to this.
Late friday afternoon, local factors had a front sensor in stock, seemed worth a shout and a chance of fixing it over the weekend.

[E-bmw]

silentbrown said:

E-bmw said:

If so what pressure did you use?

What size wheels/tyres are they?

Original wheels, Kumho runflats. 35psi (yes thats, ~5psi lower than factory recommended as the ride is hard enough to remove fillings on our local pothole-infested roads. It's tolerable at 35)

(Given it's an indirect TPM system I'm not sure why you think that's relevant?)

The question is relevant for the following reasons.

If you use the bar equivalent on most digital gauges they only display to 0.1, 0.1 bar is 1.5 psi, which can be very close to the trigger point for a TPMS warning. Whereas 0.1 psi is 0.007 bar & significantly further from the trigger point. Using psi alone can negate many TPMS alarms. You have confirmed you are using psi that means that isn't a contributing factor.

[E-bmw]

silentbrown said:

Well,quite: We've had ABS sensors fail on two other cars in the last couple of years. Identical symptoms to this.
Late friday afternoon, local factors had a front sensor in stock, seemed worth a shout and a chance of fixing it over the weekend.

Simply having the same symptoms on another car is not a reason to randomly change parts.


Job 1.
Dial up live data while driving & see what the speeds are on each sensor rather than just randomly swapping parts.

Job 2.
Test each loop with a multimeter & check for resistance, one may be different.

These are your tests on the individual sensors before changing anything.

[silentbrown]

E-bmw said:

Dial up live data while driving & see what the speeds are on each sensor

I don't have a dedicated scan tool, and had thought that feature wasn't available via a phone app (torque pro, carista) - but it looks like I might have been mistaken,
Will certainly take another look at that. The code doesn't indicate a particular ABS sensor, which is odd.

"Checking with multimeter" sounds great in theory. In practice, you've still got to jack the car, remove wheel, partially remove inner wheelarch trim, disconnect ABS sensor from harness, unclip wiring, realise your meter probes are way too short to reach the contacts in the plug, fiddle bits of wire into the plug to extend the probes, etc... And repeat for each wheel.

[E-bmw]

silentbrown said:

E-bmw said:

Dial up live data while driving & see what the speeds are on each sensor

I don't have a dedicated scan tool, and had thought that feature wasn't available via a phone app (torque pro, carista) - but it looks like I might have been mistaken,
Will certainly take another look at that. The code doesn't indicate a particular ABS sensor, which is odd.

"Checking with multimeter" sounds great in theory. In practice, you've still got to jack the car, remove wheel, partially remove inner wheelarch trim, disconnect ABS sensor from harness, unclip wiring, realise your meter probes are way too short to reach the contacts in the plug, fiddle bits of wire into the plug to extend the probes, etc... And repeat for each wheel.

Actually, in saying "check each loop" I meant the full loop from the ECU to the sensor, that way you also rule out/in dodgy plug etc.

Although a lot of what you say is required actually isn't, it is generally a 15/20 min/wheel job, which can save lots of time/money doing random swaps but hey-ho.

[silentbrown]

silentbrown said:

...thought that feature wasn't available via a phone app (torque pro, carista) ...

Carista has it - I'm sure that's a fairly new feature: "Rear Right Wheel Speed : 158.4 mph"

Taking that wheel off shows a rather different problem. Our driveway is far from flat, so I hadn't noticed the odd rear stance until I found I couldn't get the jack underneath easily...



Looks like the spring has bust (thanks, Hereford potholes) and then damaged the sensor cable which runs directly underneath it. So now into a pair of rear springs, ABS sensor (and probably discs and pads while we're at it.

[silentbrown]

silentbrown said:

Looks like the spring has bust (thanks, Hereford potholes) and then damaged the sensor cable which runs directly underneath it. So now into a pair of rear springs, ABS sensor (and probably discs and pads while we're at it.

All sorted now, but to add insult to injury one of the front struts has now ejected all it's oil. Roads here are truly shocking...

I'd planned to keep runflats to avoid daughter getting stranded with a flat, but I suspect the combo of runflats and potholes makes it more likley she'll be stranded with knackered suspension .