ABS light stays on
This solution is for every car owner with an ABS problem (e.g. Brake System Warning Light).
1)ABS warning light comes on occasionally while driving, warning light turns off next time you start the car, eventually the light comes back on if you drive long enough
2)ABS light comes on seconds or minutes after starting or even moving your car
3)ABS sensors have been replaced, ABS controller has been replaced, and ... the problem returns, sometimes soon, sometimes later
4)ABS warning light refuses to act up in front of your mechanic
5)ABS mechanic has no idea what is wrong
6)ABS brake have no leaks to be found, the brake fluid levels are normal and the brake pads pass inspection but the light comes on
My solution will not solve all ABS system warning light problems, but it may solve very many and save many dollars.
This solution just isn't Standard Operating Procedure in our day to day service repair shops as it is time consuming fault elimination. Why is it overlooked, who knows? It should also, in my experienced opinion, be the absolute first thing checked, by the book, before any sensor, control module, brake fluid, brake bleeding, whatever your mechanic suggest... the list goes on for some car owners. The point is, if this isn't checked first, all bets are off for the DIY or even the certified mechanic.
To get my point across to every car owner and MECHANIC will require GREAT effort on my part otherwise this information will be ignored. Now, back to my point, unless this check is made before any car "computer" throws an error code is taken into account, then that error code can be misleading. No ABS red warning light on the dash of all cars or trucks everywhere can truly be CERTIFIED in testing if this process isn't first completed. The odd exception might be the ABS control unit was on fire, you drove the brakes down to metal or some other freak accident. Here's where I say, "for just $9.95, you, can buy this instruction book". Nope this is FREE and will save many people from having nightmares considering the millions of car owners.
Have you ever heard, "A chain is only as strong as its weakest link"? Well, in the real world, ABS errors are almost always misdiagnosed in first repair attempts. The very first thing that should be performed is a visual inspection inside the engine compartment and brake area. Unless there is an obvious loose wiring harness plug, a lost kitten, distorted/bent brake lines, worn out rotors or brake pads, or something else screaming for your attention; then close the hood and step away from the vehicle and put down that silly diagnostic computer. So, now that the hood is closed, we are going to jack up the car and take off a wheel. Once a wheel is off, we need to disconnect the brake caliper and hang it to the side out of the way. Yes, this is usually a painful, very greasy and dirty process; front wheel and four wheel systems are even more fun. Start with the front wheels and work your way around. Now, and only now is it possible to check each Wheel Bearing Torque value. However, just checking the torque with a push and pull of the rotor disk isn't always sufficient. The hub axle bearings and bearing seats need to be inspected, bearings repacked and then precisely torqued. And when I say precisely, in some rare cases that can mean putting all the parts back together, driving the vehicle, tearing the wheel back down and checking the torque settings again. In some cases; hub, axle and wheel bearing assembly just can't maintain this torque value and still rotate properly because just one of the 3 parts may have some flaw, and this leads to rotor movement. It is also very easy for an experienced mechanic to get it wrong. So, it is good to do it right the first time but that also does not mean it always can be done correctly the first time. As good as any mechanic or auto production line worker may be during assembly of these components, all of these bearing components will never "seat" the exact same or show identical performance. They just try to do their best with what they have.
Basically, the ABS electronics are not the weakest link in most cases. If you have proven beyond doubt that the axle bearings are as close to 100% of factory torque settings and the bearings are healthy and lubed, then the weakest link has been removed. Only then should an ABS error code be used to diagnose a possible electronic component failure. All that this axle bearing nonsense means to those still wondering is that the ABS sensor ring will no longer be deflecting off axis as it spins or sits inside the rotor hub. If the hub/ABS sensor ring tilt off axis just a fraction of an inch on some vehicles, the gap between the sensor and ring is affected, and this will trip the ABS warning light. These ABS systems were designed to operate within a specific set of tolerances and unfortunately the bearings in your axles will not always cooperate. A pot hole here, a curb there, too much hard cornering and braking; sometimes that is all it takes to just slightly loosen an axle bearing and have virtually no noticeable effect.
That is my 2 cents the ABS problems, thanks for reading.
1998 Volvo V70
on Aug 17, 2019