The TPM (Tire Pressure Monitoring) or RDC (Reifen Druck Kontrolle) is a crucial system in your BMW car. It became standard in all vehicles manufactured after 2007, but what does it do? A TPM system monitors the tire pressure of all four tires and informs the driver if it falls down to 20% of its recommended value. However, it can malfunction in case any of its components has a fault. The following are the most common causes of TPM system failure:
- Defective TPM System Sensor
- Faulty RDC Module
- Erroneous Sensors Batteries
- Communication Problem
- Damage from Water
- Faulty TPM Fuse
- Mechanical Damage
Read on for more information about the TPM system and how it works. We will also explain these most common causes of failure in detail and how to reset the dashboard TPMS light.
Table of Contents
What is TPM on a BMW, and How Does it Work?
Tire Pressure Monitoring (TPM) system or Reifen Druck Kontrolle (RDC) in German is an electronic system consisting of sensors, transmitters, and a control module. Its purpose is to monitor the tire pressure of each tire and alert the driver if it falls 20% below the recommended value. It does that by turning on the dashboard light and/or displaying a warning message.
Sensors in each wheel constantly monitor the pressure and relay that information wirelessly to the RDC module. This module then communicates with the onboard computer to display an error message on the information center or turn on the TPM system light.
The TPM system warning light usually illuminates when the TPM system goes faulty. On the other hand, error messages vary depending on the car model.
Can I Drive with BMW TPM Malfunction?
Yes. You can drive with a BMW TPM system malfunction in case your tire pressure is still within the recommended value. When one or more of the tires have a low tire pressure, the TPM system warning light on the dashboard is constantly on. Don’t drive your car if it has conventional tires. Instead, go to the nearest filling station or auto repair shop to add tire pressure. Cars with run-flat tires can go for another 200 miles at 55 mph even with low pressure.
On the other hand, if the TPM system dashboard light flashes, it indicates a fault in the system, but not low tire pressure. You are safe driving your car in this condition, but you should have it fixed ASAP.
Reset the BMW TPM warning
Resetting the BMW TPM warning takes just a few minutes. If you get it on the highway, the first step is to pull over and check for a flat tire or visible pressure drop. If there is a minimal loss of tire pressure, you can carefully drive to the nearest service station and add more air into the tires.
Inflate all the tires to the recommended pressure. Most BMW models need about 32-36 PSI of tire pressure, with the exception of BMW models with low-profile tires that require up to 45 PSI. But to be sure, check a sticker on the inside edge of the driver’s door for this information.
Once you inflate the tires to the recommended pressure, proceed as follows to reset the TPM warning:
- Press the iDrive knob and choose vehicle settings.
- Scroll down and select Vehicle Tires.
- Turn the iDrive knob to choose the TPM menu.
- Select Reset and then press the iDrive knob to initiate the action.
- Select YES, and it should show Resetting TPM.
- Take a short drive to see the Status changing to TPM Active.
You have successfully reset the TPM warning. If the problem reoccurs, take your car to a qualified mechanic to conduct a further diagnosis.
Error Messages Possibly Popping up When TPM System Goes Defective
The error message displayed on the iDrive screen depends on the car model and the type of fault. Typically, it will be any of the following:
- TPM inactive warning light on the dashboard.
- Tire Pressure Monitor (TPM) malfunction:
- System unable to detect tire pressure loss
- Check tire pressure manually.
- Continued driving is possible.
- Consult service center
- Tire pressure monitor reset: System inactive and unable to detect pressure loss for up to 12 minutes. Reset only occurs while driving.
- Low tire pressure. Stop carefully. For a Run Flat tire with the “RSC” symbol, you can continue driving with max. 50 mph (80 km/h).
- A Tire Pressure Monitor (TPM) for the detection of flat tires is currently unavailable. Please contact the nearest BMW.
- Tire Pressure Monitor TPM for the detection of flat tires is currently unavailable. Don’t hesitate to get in touch with the nearest BMW.
- TPM Status: TPM Malfunction
- Unable to detect any loss of tire pressure. Check tire pressures manually
- Tire Pressure Monitor malfunction. Drive moderately. System unable to detect tire pressure loss. Consult the service center.
BMW TPM Malfunction: Causes and Fixes
The BMW TPM system malfunction results from a fault in any of its components. The dashboard symbol flashes and a related error message appears on the iDrive screen. The following are some of the commonly reported causes:
Defective TPM (RDC) Sensors
TPM (RDC) sensors on the wheels measure the tire pressure. If one or more is faulty, it transmits erroneous information to the module. The module interprets that as a fault and triggers the onboard computer to display an error message and/or turn on the TPM system dashboard warning light.
Replacing the RDC sensors is a complicated and delicate process. Consider taking your car to a qualified mechanic if you don’t have the experience and tools for the task.
Erroneous Sensors Batteries
RDC sensors run on lithium-ion batteries. The batteries can last about ten years, but it depends on the sensor type. Once the batteries run out, sensors stop working. And since the batteries are not replaceable, you will have to buy new sensors.
Once again, replacing sensors requires skills and tools. Contact your mechanic to help you out.
Faulty RDC Module
The RDC module processes all the sensor data and communicates it to the onboard computer. This unit often gets damaged from corrosion that can interfere with its operation.
After close inspection, you may need to fix or replace a faulty RDC module. So, the first step is to know where it is in your car and take it out. Usually, you will find it close to the spare wheel tire mount. Detach the wires and unscrew the faulty RDC module from the chassis and replace it with a new one.
Damage from Water
Newer TPM system generations rely on one control unit usually mounted on the chassis. As a result, water can sometimes penetrate the casing and damage the electronic components.
Corrosion can cause permanent damage, which requires the replacement of the entire RDC module. If you are lucky, cleaning can fix the problem. But if you are an advanced DIYer, you can check how to do it in the video below.
Communication problems occur when transmitters are defective. They pick up signals from sensors and transmit them wirelessly to the central control unit.
The transmitter or reception antennae on the central control unit can become defective, leading to a break in communication. Therefore, a further diagnosis may be necessary to determine the actual cause and replace the faulty component. You need a skilled mechanic for that.
Faulty TPM Fuse
The TPM system fuse can blow out if a short circuit occurs in the RDC module. Check the junction box behind the glove compartment to locate this fuse. It may also not be there in some models. Refer to your vehicle repair manual for more information. Once you identify it, just replace it with an appropriate one.
TPM system malfunction is rare. But if it occurs, the most likely culprits are the sensors, control module, or transmitters. If any of these components is defective, the system will not monitor the tire pressure. Thus, you won’t know when it is falling dangerously low, which puts you at a higher risk. Once you get the TPM malfunction warning, take your car to the nearest auto repair shop or contact your mechanic as soon as possible.