Troubleshooting ABS sensor? Or wire?

[Jackmnemonic]

2008 MK5 GTI here. I had to change the CV boot, and that was simple but messy. Now the traction control and ABS lights come on and stay on. Code reader doesn't recognize any faults.

How do I determine if the sensor spontaneously went bad or if I pinched the wire shifting the axle in and out too many times? Resistance check? Continuity check? What's it supposed to be?

TIA

[colesey]

Has the wheel alignment been checked? I had something similar and a code for steering angle sensor came up as the toe setting was out of kilter. 

[LC5F]

If you left the sensor connected all the time you were working, I would say it's more likely to be the sensor has been knocked - they tend to go brittle over time. The outer sheath on the ABS loom is quite robust, you would really have to lean on it to damage it.

If you disconnected the ABS sensor and switch on the ignition (to turn the steering) it will think the sensor is missing and save it as an error - VW does not let critical safety errors clear themselves, and not all code readers clear these errors.

Either way it will need to be cleared, it seems you need a better code reader that can clear ABS

[pudding]

Has the wheel alignment been checked? I had something similar and a code for steering angle sensor came up as the toe setting was out of kilter.

That doesn't change doing a CV boot.  The (OEM) ball joint and strut can only go back to their original positions.  It's only messing with the console bushes and/or subframe that throws the alignment.....or in your case, adjustable ball joints not restored back to their original aligned position.

[Tharkhold]

Stupid question here, is the warning light yellow or red?

Also, VCDS would tell you immediately if it's a circuit fault or sensor malfunction.