MK7 2.4 RWD - ABS / ESP lights & No speedo

[Coley3159]

Just double checked the batteries and the front auxiliary battery was only reading 12.1V and the rear starter battery where the solar system is connected was reading 12.9V.

I guess my solar system doesn't charge the front aux battery when the van is not running and locked. Correct me if im wrong but the two batteries are disconnected when the ignition is off and the van locked until the ignition is turned on and the sure start system utilizes both batteries and then the connection remains to change both via the alternator until the ignition is switched off again?

My transit is a camper and not regularly used so obviously the front auxiliary battery is taking a beating.

Charging the front battery overnight to see if that makes any difference.

[Coley3159]

Ok so charged the front aux battery for around 4hrs before heading off to work and it was up to 12.9V, the charger was reading half charged so will get it charging again tomorrow.

Started the van and the ABS/EPS lights and ---- was still there.

Restarted and both lights went out and everything was back to normal.

Maybe this is a case of just a slightly drained front Auxiliary battery?

Although I thought the reading I took of 12.1V before charging meant the battery was about 40-50% charged?

I also checked the batteries with the engine running and both are receiving 14.4V from the alternator.

[knobby1]

Ok so charged the front aux battery for around 4hrs before heading off to work and it was up to 12.9V, the charger was reading half charged so will get it charging again tomorrow.

Started the van and the ABS/EPS lights and ---- was still there.

Restarted and both lights went out and everything was back to normal.

Maybe this is a case of just a slightly drained front Auxiliary battery?

Although I thought the reading I took of 12.1V before charging meant the battery was about 40-50% charged?

I also checked the batteries with the engine running and both are receiving 14.4V from the alternator.

Check the front battery after being sat overnight....the front battery does all the work when the van isn't running....alarm, clock etc...Rear battery just sits there.

Lord Knobrot

[Coley3159]

Front aux battery was reading 12.6V and no lights when the ignition was turned on, seems to be holding a charge so hopefully the battery isn't damaged.

If a discharged front battery is the underlying issue im glad I double checked before moving earth points and swapping out ABS sensors.

Thanks Knobby!

[Coley3159]

Update!

The issue that was causing all the problems was the front near side wheel bearing. I had this changed and not had a problem since. Its crazy that this can give a ABS no communication fault when reading with Forescan.

[metalworker0]

Think ....don't quite know or sure of this... so..i'm probably asking

That when the wheel bearing starts breaking up internally, it spreads metal swarf around the inbuilt reluctor rings ..that cause signal error.

all the best.mark

[Coley3159]

It throws the wheel speed sensor / abs sensor off giving an incorrect reading and then causing the fault code.

[knobby1]

It throws the wheel speed sensor / abs sensor off giving an incorrect reading and then causing the fault code.

A failing bearing essentially moves the reluctor ring away from the sensor....replacing the bearing brings it back in line again.

Lord Knobrot

[andz327]

Must have been hanging off as I've had noisy slightly worn wheelbearings and never caused an ABS problem on these

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