we started to get “service vehicle soon” and the ABS symbol lighting up on one of our staff member’s C5, it was hard to figure what was going on at first, because just as suddenly as these messages appeared, they would also go away for no apparent reason. Our initial prognosis was that there was an electrical problem – perhaps an intermittent short somewhere       in the system. We did notice, however, that hitting a hard bump would bring the messages on and hitting another hard bump would usually make them go away – although most times they would go away on their own after a few seconds. We did a code check and we got a “C1222 Right Wheel Speed Sensor Input Signal is 0”. So that’s how we found out the the cause of this was a faulty wheel speed sensor jumper harness on the right front wheel. Installing a new wheel speed sensor jumper harness isn’t difficult – it’s pretty much a plug and play affair. But getting to it can be a challenge. It’s much easier to do it if you jack the car up, support it with jack stands, take the wheel off and disconnect the tie rod. And, while you can do this in your driveway, if you have access to a lift life is much easier for projects like this.