BMW Won’t Start Due to IBS Sensor Fault

BMW Won't Start Due to IBS Sensor Fault

This article will discuss the BMW intelligent battery sensor, also known as the BMW IBS. We will explain what the IBS sensor does, common problems associated with the sensor, and how to troubleshoot IBS problems yourself.

Symptoms of a Bad IBS Sensor

  • BMW battery will drain when parked
  • BMW will not go to “sleep,” drains the battery
  • IBS is not able to wake up the DME
  • Voltage fault, DME not on. This can be caused due to a short at the B+ line.
  • Voltage fault DME on, which can be caused to ground short
  • Dead car battery, the car won’t start

What is BMW Intelligent Battery Sensor

The BMW intelligent battery sensor is connected to the battery’s negative terminal. BMW cars depend greatly on the battery for starting the engine and many other functions.

Battery plays a critical role in BMW cars. The Intelligent Battery Sensor (IBS) monitors various battery parameters such as voltage, current, and temperature.


The IBS sensor is mounted on the battery negative terminal with a ground cable and two connectors. One of the IBS cables connects gets power from the positive terminal. The second cable is connected to the DME and measures the battery load. This is known as the Bit Serial Data Interface or BSD.

BMW IBS sensor measures several battery parameters such as:

  • Terminal Voltage
  • Charging current
  • Discharge current
  • Battery Temperature
  • SoC (State of Charge)
  • SoH (State of Health

How to Troubleshoot BMW IBS Sensor


We scan the DME module for fault codes to determine if the IBS sensor on BMW is defective. You will need a BMW diagnostic scanner, such as the YOUCANIC Full System Scanner that can read fault codes on every control module of your vehicle.

  1. Locate the OBD-II port under the dashboard, driver’s side.
  2. Plug your diagnostic scanner into the port.
  3. Turn on the ignition but do not start the engine.
  4. Turn on your scanner and allow it to communicate with the onboard diagnostic system.
  5. Select your BMW make and model.
  6. Go to Control Units.
  7. Select DME from the menu.
  8. Select read fault codes.

Fault codes related to the IBS sensor are stored in the DME module. The DME will check the current, voltage, and temperature.

These messages may be stored in the DME module if there is a problem with the IBS sensor.

  • Voltage Fault
  • 299B DME Intelligent Battery Sensor
  • 002E8D DME: Intelligent Battery Sensor, signal transmission

How to check for IBS Sensor Recall

From time to time, BMW may recall vehicles if they have been manufactured with safety defects.  To find out if your BMW has an IBS sensor recall, you need to call the dealer and provide them with the VIN or check for recalls online.

How much does a new BMW IBS Sensor cost?

A brand-new BMW IBS sensor costs anywhere from $150 to $250, depending on the series. Search for  BMW IBS Sensor on eBay online.

Can I bypass the IBS Sensor on a BMW?

Disconnecting the IBS cable from the negative terminal will disable the IBS communication with DME. This is not a solution. Bypassing the BMW IBS sensor is not recommended. If you bypass the IBS sensor, no information from the battery and its charge status will be available for the DME.

Additional Resources

  1. BMW TIS – Intelligent battery sensor_ E60, E61, E63, E64 Installation location Item Description.pdf
  2. BMW IBS “ Intelligent Battery Sensor “ What Is It, What Does It Do?
  3. BMW Intelligent Battery Sensor (IBS)

We hope you find the BMW Won’t Start Due to IBS Sensor Fault guide helpful. Check these troubleshooting and repair guides for more help on your BMW.

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