The other morning I get into my Infiniti G35x and as I head out the driveway, I notice that my ABS, VDC, AWD, and SLIP lights are all illuminated. This is not a good situation, as luck would have it, the areas first snow storm was expected later that day. The car drove normally during my 35 mile commute, however I was able to determine that yes, the car was only in RWD mode, and the traction control was not operating. After searching on the web, I found a couple suggestions, including low brake fluid. As I drove over to the local auto parts store at lunch, I was pretty sure that was not going to be the issue. As I pulled into the parking lot, I suddenly remembered that I had run over some twigs in the road the night before. Thinking maybe something got stuck in the wheel, I turned the front wheel all the way to lock.
Imagine my surprise to see the left wheel wheel filled with a black plastic fencing material that had wrapped thousands of times around the front drive shaft. Clearly this was the issue, either it was causing the wheel sensor to not work, or it had ripped out the wiring to the wheel sensor. After jacking up the front end and removing the left wheel, I spent the next 30 minutes cutting and unwrapping a very large amount of plastic fencing from around the drive shaft. I noticed that the front wheel sensor is a press-fit into the wheel hub where it extends out close to the ring around the wheel hub that is used to measure wheel speed. The sensor had been pushed out, which increased the distance from the hub ring enough so that it would not function.
The Infiniti’s ECU uses the wheel speed sensor to determine if a wheel is locked up or spinning at a different rate from the other wheels. This is what allows it to control the ABS (anti-lock brakes) and VDC (Vehicle Dynamic Control – Traction Control). The ECU is also smart enough to disengage the all-wheel drive if these systems are not functioning properly.
Once I pushed back the sensor, the ECU again realized that it was receiving signals from the wheel sensor, and all the warning lights went out. So, if you have all of these warning lights illuminate at one time, and you know your brake fluid is topped off, check your wheel sensors. They may have been dislodged, the wiring damaged, or they may simply have failed. A quick inspection could save you thousands of dollars in repair bills. In the following diagram, item 8 is the wheel speed sensor.