Seems to be a common problem and you can find a **** post from me further on after finally cracking the problem.
Here is what I learnt.
If you are driving along and these warnings appear you can draw three conclusions:
It is not the reluctor or impulse ring
It is very unlikely to be the ESP or ABS electronic unit
It is one of the sensors with a bad contact where it is plugged into the wiring harness and not the actual sensor itself which is pretty bombproof.
If you switch on the ignition and don't move the car or start the engine and you get these lights, it is the sensor connector
If you have these lights after driving, clear them and then see if they come back when you switch on the ignition and don't move the car.
If your car is a rusty old banger then yes, it could be the impulse ring of the old type
Why is this?
The car will signal a fault if it detects no circuit to the sensor which happens only when there is a bad contact ( reseat the sensor plug)
When you move the car and one sensor is duff then there is a DTC to say 'implausible signal from wheel speed sensor'
The car detects movement via all or any of the sensors and only then will it raise the above DTC and the ABS/ESP lights - otherwise not.
If all the sensors have electrical contact and no bad contacts and the car is NOT moving and there are no stored DTCs, the ABS/ESP lights won't light. Clear DTCs to test this.
I spent a lot of time chasing the reluctor ring and learning how to change it but it was a wild goose chase. It is a static component and will last decades unless rusted to death.
Moral. Reseat the sensor contacts first
Here is what I learnt.
If you are driving along and these warnings appear you can draw three conclusions:
It is not the reluctor or impulse ring
It is very unlikely to be the ESP or ABS electronic unit
It is one of the sensors with a bad contact where it is plugged into the wiring harness and not the actual sensor itself which is pretty bombproof.
If you switch on the ignition and don't move the car or start the engine and you get these lights, it is the sensor connector
If you have these lights after driving, clear them and then see if they come back when you switch on the ignition and don't move the car.
If your car is a rusty old banger then yes, it could be the impulse ring of the old type
Why is this?
The car will signal a fault if it detects no circuit to the sensor which happens only when there is a bad contact ( reseat the sensor plug)
When you move the car and one sensor is duff then there is a DTC to say 'implausible signal from wheel speed sensor'
The car detects movement via all or any of the sensors and only then will it raise the above DTC and the ABS/ESP lights - otherwise not.
If all the sensors have electrical contact and no bad contacts and the car is NOT moving and there are no stored DTCs, the ABS/ESP lights won't light. Clear DTCs to test this.
I spent a lot of time chasing the reluctor ring and learning how to change it but it was a wild goose chase. It is a static component and will last decades unless rusted to death.
Moral. Reseat the sensor contacts first