2006 Chevrolet Impala



August, 30, 2012 AT 5:54 PM

2006 Chevy Impala SS - 95K miles

I was driving the other day and both the "service traction control" and "service brake assist" displayed on the dash, with the ABS light illuminated. I took it to a shop and got the code C0040, which is the right front speed sensor. Since the senor only comes on the hub, I have to replace the whole assembly.

The day before I got these messages, I had changed my car's oil, and since I had spilled some, I was using a water hose to spray under my vehicle and close to the passenger tire. Is it possible that this may have damaged (temporarily or permanently) the sensor? I also notice a slight skid or drag sometimes when I apply the brakes, and after is when the alerts come up. They go on and off.

3 Answers



August, 30, 2012 AT 5:59 PM

A trouble code does not necessarily mean a component is fault. It can be other factors such as contaminations or loose connectors. The code only tells you a problem has occurred with the circuit.

Since the problem is intermittent, it is possible the hosing has contaminated the sensor wire connectors or gears. You can try removing the sensor and clean the reluctor gears with compressed air to see if it helps.



August, 30, 2012 AT 6:27 PM

I appreciate your response. I hope that I can see if that works without putting the wheel back on and driving it, because I already bought the hub assembly and I'd like to just change it while I have the wheel off the first time if need be. Whatever the cause may be with this speed sensor, could it cause the braking issue that I explained, or could this be an issue with the actual brakes? I think it's too much of a coincidence that it happened the day after spraying, so I think that is the issue, but I can't be sure of course.

Also, when replacing the hub, I read that I need a thread locker on the bolts upon reassembly, and lithium grease on the spline of the axle. Are these completely necessary?



August, 30, 2012 AT 7:43 PM

The ABS sensors receives signals from the wheels to operate the modulator and if any fault is detected, they would not work correctly which can result in skidding. Once the light comes on, the ABS system has been disabled.

What I understand is that the sensor has most probably been affected by the hosing and if the damage is reversible or not, you need to inspect and perform testing to find out.
Actually you are required to replace the bolts which comes with the self-locking materials. Without it the nut might work itself loose over time.

As to the grease, it is required to prevent rust which can cause the splines to fuse with the bearing hub and prevent future removal.

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