When the BMW ABS (Anti-lock braking system) module fails it triggers warning lights such as ABS, Brake light, and DSC warning lights which is one of the most common BMW problems. In a few cases, the speedometer stops working.
ABS and Brake orange or red warning lights come on at the same time due to this problem.
DSC problems at first may be intermittent such as only coming on when driving over 30 mph or only when the engine is hot. Other symptoms include ABS pump constantly running, draining the battery.
In this article, we discuss most common BMW DSC problems, symptoms, causes, possible solutions and how to reset the DSC light on a BMW yourself.
Reading the codes will help you pinpoint why your BMW DSC and ABS are staying on.
If the DSC light comes on as soon as you start to drive, this typically indicates a problem with one of the wheel speed sensors. But it can also be an issue with the wheel speed sensor wire or the ABS module.
While you can still drive your BMW even if the DSC light is on, you may be more likely to get into an accident under extreme maneuvers or inclement weather conditions. Do not drive if the BRAKE light stays on.
It is unlikely that you will cause any further damage to your car by driving with the DSC system disabled.
Diagnose your BMW as soon as possible if BRAKE light stays on. A problem with the brake system could result in a fatal accident.
DSC stands for Dynamic Stability Control. Its main purpose is to monitor the vehicle and help keep it stable and driving in the intended path. The DSC system is always enabled by default. Under normal operation, the light DSC light on the instrument cluster should be off.
DSC system monitors input from several sensors of your BMW to determine if the vehicle is driving in the intended path.
For example, the DSC analyzes data from the steering angle sensor, yaw rate sensor, ABS wheel speed sensor, automatic transmission, brake pedal etc. If it detects that the vehicle is losing traction or wheels are spinning, it will apply brake pressure to help keep the BMW on the right path.
DSC is always working to help you be safe on the road. If you want to partially disable the DSC, you can do so by pressing the DTC button on the dashboard. Hold the DSC / DTC button pressed for at least 3 seconds.
When the DTC is disabled, the DSC light turns on in your instrument cluster. What this means is that the DSC system will not interfere with your driving unless there is a critical condition. Some systems will still remain active (such as electronic locking differential) even when the DSC is turned off.
The first thing you should try is press and hold the DSC button on your dashboard. The button may have been pressed accidentally and disabled the DSC.
The next thing that you can check yourself without any tools is the brake fluid level. Low brake fluid level can trigger the DSC, ABS and Brake lights. If you notice that the brake fluid is low add OEM BMW brake fluid if you can or use Pentosin DOT 4 LV Brake Fluid which is the recommended brake fluid used on BMW and cost less. Don't use old brake fluid as brake fluid that has been sitting for a long time. Moisture can cause the brake fluid to become acidic over time.
ABS pump might randomly malfunction and set a fault code in the DSC module. Try unplugging the ABS pump and reconnect it. Make sure the key is removed from the ignition when you do this. Restart the car and check to see if the DSC light has turned off.
If any of the tips mentioned above didn't turn off the DSC light, you need to read the fault codes. There could be a thousand reasons why the DSC light has turned on in your BMW and without the proper diagnostic you be just guessing.
You will need a BMW specific OBD2 scanner. Most OBD2 code readers you find online won't work.
Two very affordable scanners that can read and clear DSC does from BMW such as E39, E90, E46, Z3 etc are Carly for BMW and Foxwell NT510 for BMW. If you would like to learn more about BMW specific scan tool read this article on Choosing the Best Scanners for BMW.
The following scanners are capable of reading and clearing codes from multiple BMW systems, not just the ECU. Our recommendations are:
Both these scanners are affordable and can read and clear BMW DSC fault codes.
Locate the OBD2 port on your BMW. It is under the dashboard next to the hood release. Plug your BMW scan tool.
Turn on the ignition but do not start the car. Key should be in position II. All dash lights will turn on when the key is position II.
Read codes from the DSC module. Research the error code online. Consult an independent BMW shop or the BMW dealer if necessary to get a better understanding of the problem, causes, and possible solutions.
Address the problem. Once you fix the problems reconnect the BMW scanner and clear the fault codes. Drive the BMW for a few minutes and rescanned to check if any of the codes came back.
Let's watch a video on how to read and clear codes from the DSC module using Foxwell NT510 for BMW.
You won't be able to clear the fault codes until you fix the issue that triggered the code in the first place. Codes that have been triggered in the past but currently are not an issue or active will be saved as a shadow or stored codes. Those can be erased.
If the module doesn't respond it is possible that the ABS module is "frozen" for lack of better word. Try unplugging the wire harness from the ABS module and reconnecting it. Otherwise, you may have a defective ABS unit.
Check steering wheel angle sensor
Make sure that the steering wheel angle sensor isn't defective. The only way to find out if that's the case is to use a BMW specific diagnostic scanner. You will be able to check if there are any fault codes that point to a defective steering wheel angle sensor. In some cases, you may need to perform a steering angle sensor calibration.
Drive the car. Rescan for codes
Drive your BMW even if it is for a few minutes to see if the DSC light will come back on. DSC light is generally triggered as soon as you start to drive especially if there is a problem with the ABS pump or the wheel speed sensors. That's why you should always drive your BMW and verify the DSC light doesn't come back on. Once you perform a test drive, rescan for codes just to be sure.
Here is a list of typical BMW problems that can trigger the DSC / ABS/ Brake lights. We strongly recommend that you read the fault codes before you replace any parts. Always read the codes and consult an auto mechanic that specializes on BMWs or the dealer for more help.
The wheel speed sensor (or ABS wheel sensor) is one of the most common problems that can cause the DSC light to come on. These sensors fail due to water damage, dirt or metallic particles collected on the magnetic part of the sensor.
You shouldn't replace the wheel speed sensor without first confirming it is the culprit. Replacing a wheel speed sensor is easy on a BMW but don't throw parts at your beemer if it doesn't need it. Read the codes before you replace the wheel speed sensor.
If you replaced the wheel speed sensor and are still getting the same error related to wheel speed sensor failure it is possible that the wires to the sensor are damaged, or the ABS Control unit is the problem.
One way to confirm that the sensor itself is the problem and not the wires or the ABS module is to start by reading the codes. Let's say it points to a bad right rear wheel speed sensor. Swap the two rear sensors and drive the car.
Did the error move to the other wheel? If it did, then you know the problem is the wheel speed sensor because the error moved with the sensor. If the error is still pointing to the right rear wheel then you may have a cut wire or a bad ABS module.
When replacing BMW wheel speed sensors, it is strongly recommended to stay with OE BMW wheel speed sensor. Aftermarket BMW wheel speed sensors tend not to last as long and in some cases don't work properly.
The ABS pump may fail and trigger the DTC / ABS / Brake lights. In most cases, if you scan your BMW you will get code descriptions such as "control unit internal failure." At first you may notice these lights intermittently, but eventually, they will come on and stay on consistently.
In some cases, the yellow warning lights come on when the car warms up and may go away when the car cools down. These symptoms are often caused by broken solder joints in the ABS module circuit.
You can try unplugging it and reconnecting to see if that fixes your DSC problem. If you are getting "Communication Error" when you try to scan the ABS module that's a sign that the module may be defective.
If your ABS module fails one of the cheapest ways to fix it is to use a BMW ABS rebuilt service. These are shops that specialize fixing these common problems on BMW ABS modules. A BMW ABS rebuilt service can cost under $200 and doesn't require any coding.
A new ABS pump costs over $600-$850. On newer BMWs installing a new ABS pump will require coding to your VIN. If you take your car to any BMW dealer, this repair cost in the $1000-$1500 range. When you rebuild your existing ABS pump, there is no need to pay money for coding. You may need to clear stored codes though.
You can do that yourself using a scan tool that can read and clear BMW fault codes. If you don't have a scanner, read our article on choosing the best BMW scan tool for DIY auto repair.
There are third party companies that provide BMW ABS Module rebuild. Within 6-10 days you will typically get back your repaired ABS unit. Install it back on your BMW. Clear the stored fault codes and you are ready to go
Cars back in the 1990s didn't have ABS and your BMW will be in the same situation. The speedometer and odometer will also not work with the ABS module removed. Neither will your instrument cluster record any added miles. You will also trigger additional fault codes that will require a BMW specific OBD2 scanner to be erased.
If you have an older BMW, you may be able to get away installing a used ABS hydraulic unit without coding. Newer models need coding unless it is the original unit or you will get errors such as PT-CAN chassis number wrong or ECU not initialized.
The pre-charge ABS pump may fail. This is common if your BMW has high miles and you notice the lights at high speed such as over 30 mph or when you drive your car as if you stole it. Eventually, the lights will come on and say on all the time. When you scan your BMW, you will get error codes related to the pre-charging pump.
The reason why this happened is often the worn brushes inside the ABS pump. The more miles on the BMW, the more likely it is for these brushes to wear out.
To check if this is your problem try accelerating very slowly. If the lights don't come on this may indicate that the precharge pump is the problem. Always read the fault codes to verify that the pre-charge pump is the culprit before you replace it.
To replace the pump you will need to bleed the brake system. Remove the pump and install the new one. Read this article on how to replace BMW ABS pump. Some BMW pumps may not be replaceable.
Since the pump is simply an electrical motor, installing a used pump would be fine as long as it is the same part number. Another alternative would be to open up the motor and replace the brushes yourself.
If your BMW has the DSC and the brake light on, it is very likely that the problem may be the pressure sensor mounted in the brake cylinder. In most cases, the ABS light does not turn on, only the DSC and brake light. Codes that may present when you scan the DSC module include:
To verify the sensor is the culprit you can swap the two sensors. Let say the error code pointed to Sensor 1 but after the swap it now moved to Sensor 2 location you know that the problem is the sensor. If you are still getting the error code pointing to sensor 1 it is likely that the problem is the ABS unit and not the sensor.
Low fluid level can trigger the brake light and in some cases the DSC warning light as well. Open the hood of your BMW and locate the brake fluid reservoir.
High voltage or low voltage may trigger the DSC light and other lights on BMW.
This can be caused by a faulty alternator, bad voltage regulator or a defective BMW battery. BMW cars are extremely sensitive to low voltage.
If that is the problem, you may notice other problems such as BMW going into limp mode.
This problem can affect all BMW models including 3-series, 5-series, 7-series, X3, X5, Z-series.