The Anti-lock Braking System (ABS) aims to ensure your BMW 328i wheels don’t get locked while you apply the brakes. However, the ABS light might pop on your dashboard in many cases just like that!
So, what causes the BMW 328i ABS to light in the first place? A bad wheel speed sensor, low braking fluid, damaged sensor wire, and a faulty ABS control module are a few of the root causes of the ABS light-on trouble! That’s not all; blown fuse and low tire pressure are also responsible for this ABS light issue.
Therefore, in this article, we’ll guide you through all the reasons for this ABS light problem and provide the best solutions to counter them!
Possible Causes and Solutions for the BMW 328i ABS Light Always On
Below are some of the possible causes for the ABS issues, along with the expert solutions that can help you fix the trouble.
1. Faulty Wheel Speed Sensor
Each wheel hub on this BMW comes with an ABS sensor that aids in tracking how fast the wheels are turning and transfers this info to the ABS. However, if a faulty sensor transmits the wrong speed information, the ABS light turns on.
It’s pretty common for the wheel speed sensor to turn bad because it’s one of those BMW components that’s mostly exposed to rough conditions.
In most cases, the best possible solution is to replace the wheel speed sensor. And here’s how you can proceed with the replacement:
Step-1: First, you need to get yourself a proper work area to conduct the replacement.
Step-2: Next, use a ½ inches breaker bar along with a set of lug nut sockets to loosen up the nuts.
Step-3: Once done, jack the vehicle and put it on the jack stand.
Step-4: Now, slowly remove your old wheel sensor. In this case, you may need to remove the rotors and the brake pads.
Step-5: Finally, install the new speed sensor and attach all the brake parts back to their location.
If everything’s perfectly set and in order, the ABS light should not be a bother anymore! Although the replacement is pretty simple, if you still face challenges, you always take the assistance of an expert.
You can consider watching this video for a better understanding!
2. Low Brake Fluid
When your BMW is in excessively low brake fluid levels, it can trigger the ABS light.
There are three possible causes for your BMW to have low fluid levels; worn rotors, damaged or worn braking pads, and a certain lead in the system.
The low-level fluid can easily be countered simply by adding fresh brake fluid to the full line. And here’s how you should do it:
Step-1: You need to open your vehicle’s hood to check the surface level of your brake fluid.
Step-2: Find the master cylinder and check the brake fluid level in your reservoir.
Step-3: Once you’re sure the fluid level is lower than it should be, replace it with new fluid. You should follow your BMW manual to know the amount you should fill in!
Step-4: Lastly, close the hood and cap the reservoir; the ABS light should turn off by now.
You can watch this video to ease your way through the fluid filling.
3. Bad Wire or Connector
There’s always a possibility that your connectors or wires are damaged or corroded, which can trigger the ABS light.
The damage or corrosion can occur for several reasons; old wires and too much exposure to dirt and moisture are some of the possible reasons.
Fixing your connectors won’t be a reliable solution when your connectors get damaged. So, all you’re left with is replacing them with new ones. Follow the steps to do that.
Step-1: Get the plug connector separated, and you can easily do this by pressing on the small button placed on top. Then slowly pull it away.
Step-2: Now, gently remove the frontal lock and get the “catches” out. You can do this with the help of a pick or even a screwdriver.
Step-3: Replace the corroded wire or connector with new ones and get them back in place. Just ensure it’s perfectly attached and enclosed!
4. Low Tire Pressure
If the wheels on your BMW come with low tire air, the ABS light might come on. When a tire is underinflated, the diameter of the wheel gets smaller. This makes the wheel move faster than the other wheels on the car.
So, when your control module sees a change in how fast the wheels are going, it sends an ABS fault code to the speed sensor of the wheel with low tire pressure.
You can simply fix the low tire pressure issue in a few simple and easy steps. Here’s how you do it:
For Tire Air Pressure Inspection
Step-1: Get the cap from your tire air valve removed and place it in a secured place where you won’t lose it.
Step-2: Press your tire gauge against your open valve stem for a couple of seconds or so.
Step-3: Once done, take the air pressure readings and check with your BMW tire pressure manual to compare the readings.
Step-4: Replace the tire’s air valve cap and repeat the entire process with all the tires.
Filling Up the Tires
Step-1: Position your BMW next to your air pump so that your air hose reaches the tires that need air filling.
Step-2: After checking the psi, place the air hose over your valve stem simply like you did with the pressure gauge.
Step-3: Once done, start filling up the tires with air and make sure to check the pressure after you’re done.
5. Bad ABS Pump
The ABS pump, also known as the HCU (Hydraulic Control Unit), is designed up of a mechanical and an electrical part that uses hydraulics.
When you hit hard brakes at top speed, the hydraulic part opens the valves to lower the braking pressure at the wheels. So, if there’s a problem with the ABS pump, the ABS light will come on, and a fault message code will be saved in your memory.
Getting your ABS pump repaired mainly requires the assistance of an expert since the process is pretty critical, and slight errors can prove expensive. However, if you already have a grip on the mechanics, below are the steps you can follow.
Step-1: Run a diagnostic test and inspect the trigger cause of the bad ABS pump.
Step-2: Next check on the ground connections and power, as faulty wiring can also be a prime cause for the bad ABS pump.
Step-3: Once done, bleed the braking system, as this will clear up any trapped bubbles in your ABS pump.
Step-4: Now, flush and get your braking fluid replaced to ensure no contamination is present.
Step-5: Get the ABS system reset (discussed in the later section) using an ABS reset tool or OBD-II scanner.
6. Blown Fuse
If a fuse blows, this can cause the ABS light to pop up. Fuses can blow due to many reasons; it can either be due to faulty wiring or defective switches. However, certain mechanical complications might also result in blown fuses.
Replacing the fuse can be easy if you know the dos and don’ts. So, below are the steps you must follow:
Step-1: Identify the place where the fuse is blown and then get the electrical appliances unplugged.
Step-2: Next, you’ll need to get your main power turned off to your fuse gearbox. This step will ensure your safety during the replacement process.
Step-3: Look for the fuse box and replace it with the new fuse. Make sure you align the fuse correctly and with the right corresponding slots in the holder.
Step-4: Once it’s done, restore the ignition of your BMW 328i and you shouldn’t have any trouble with the ABS light anymore.
Ways to Effectively Reset Your ABS Light
This section will focus on the various ways you can easily reset your ABS light. The mentioned points are confirmed by experts, so the chances of a successful reset are higher. Therefore, don’t miss any of the following!
Get Your Issue Fixed
If you don’t fix the root problem that caused the ABS light to turn on, it might be impossible to turn it off. The warning light will indeed return when the system notices the problem again.
Therefore, address the problem and carry out the solutions (discussed in the above section) first before focusing on any other methods.
Use an OBD2 Scanner for Analysis
Since BMW has onboard diagnostics (OBD), fault analysis can give an insight into where the problem is.
- Simply connect the scanner tool to your 328i before you start troubleshooting. Most of the time, the OBDII connection is under the dashboard.
- Turn your engine on once the diagnostic tool is hooked up.
- Once done, such tools will ask you a few questions about your vehicle. It’s essential that you get this exactly right, or the search results may not be accurate. You may need to type in the VIN (Vehicle Identification Number) along with the engine and model type.
Take Out the Battery
If you don’t have a tool to reset the ABS light, you can simply disconnect your battery for a few minutes.
- First, take the wire off of the negative end of the battery.
- Then, take it off of the positive end.
- Press your horn button a couple of times and get your headlights turned on while the battery’s still unplugged. This will aid in eliminating any excess power.
- After 10 to 15 minutes, connect the positive cable and then the negative in the opposite direction. And you’ll have your ABS light successfully reset!
Below are some of the frequently asked questions among BMW 328i users regarding the ABS light.
Yes, there won’t be much trouble since your 328i’s normal brakes will still operate. However, it’s always recommended that you get the fixes done as soon as possible to avoid any mishaps.
Yes, in certain cases, it can result in a brake failure. This is because when the ABS module fails, there are chances for the brake pedal to become unresponsive.
No, it won’t; since the fuel economy or consumption isn’t directly connected with the ABS sensor. So, there’s nothing to worry about!
After going through the blog, we believe you can now deal with the BMW 328i ABS light issues without any trouble. As long as you have the right guide, you can easily counter the challenges with the ABS.
However, if you’re unsure of how to inspect and deal with the problems, always take the assistance of an expert to help you out.