Can a Bad Car Battery Cause Computer Problems – (Explained)?

Problems with Car computers also called ECU or ECM can be an inconvenience – from triggering the potentially scary check engine light to, in addition, stalling your car when you least expect it.

In this post, I’ll share my take on:

  • whether a bad battery can cause computer problems
  • what issues you may experience when your car has computer problems so that you can recognize them faster, and finally
  • how best to troubleshoot computer-related problems.

What it Does | The Car Computer – Engine Control Module (ECM)

The ECM is the ‘brain’ of the car engine.

It receives information from different sensors and electronic modules in the car and uses that information to both control and ensure the safe performance of your car.

Some examples of what the ECM does in the car:

  • Stepping on the gas pedal increases both the air and fuel intake to the engine accelerating the car
  • controlling and keeping your car’s engine speed when the car is in idle

Bad Car Battery and Computer Problems (ECM)

A weak or bad car battery could in theory cause the type of problems associated with engine performance, after all, it needs sufficient power and voltage to power its internal electronics to properly manage the car’s engine performance.

Computer problems though tend not to come as a result of bad or weak car batteries.

Common causes of Car computer problems

The more common causes of car computer problems are:

  • Loose and sparking battery connections can drive spikes that damage the ECM
  • Faulty car alternator – A faulty alternator could potentially push an over voltage that dmages the ECM.
  • Some ECU’s just fail from age after many years of service
  • Poor grounding – double check the ECM’s ground connection

Examples of issues you may experience with Car Computer (ECM) problems

The car problems below may possibly point to an issue with the ECM but you need to test with a scanner to confirm so.

By using the scanner, you can read and reference the error codes in the service manual that can help you pinpoint the fault faster and save you money.

The issues

  • Random check engine light on the car’s dashboard
  • Car can fail to start or when it starts, it may sputter instead and fail to turn over
  • Running car engine can stall. It may be able to start again but can fail shortly afterwards.
    When accelerating, car can stop increasing speed even you step on the gas
  • Car does not accelerate smoothly, its jerky in its pickup
  • Blown ECM fuse

There are other potential causes of problems similar to those related to ECU/ECM failure like faulty or disconnected sensors – so it is not so clear cut!

Note: These are only some of the issues – each car and situation is different and this list is by no means exhaustive.

You may also be interested in: How many Volts a Car Battery needs to Start?

Typical Power requirement of an Electronic Control Modules

The recommended voltage of a typical ECM for a sedan is 12V.

What else can causes ECM problems?

In addition to the possible causes of failure above your car’s ECM can also fail if:

Poor workmanship, there have been some recalls of Toyota – many years ago.

It is worthwhile checking with your dealer or forums for your specific car model if the issue to isolated to your car only or if it is a general issue.

ECM can also fail if it is accidentally exposed to water during an engine car wash – some ECM’s are located below the passenger seat while others are located behind the glove compartment.

Do not splash water in these areas to avoid damaging your ECM.

Pinpointing and Fixing Car Computer problems

It is common to suspect ECM. Unfortunately, issues that can be associated with ECM failure can be caused by other faults – for example, a faulty fuel pump.

Instead, you can save yourself both time and money by having the ECM tested.

You can confirm the cause of your car’s computer problems by connecting a scanner to access and read the error code that is generated by the ECM.

You can also take your car to an Autoparts store to read your ECM and properly diagnose the underlying problem.

Final thoughts

Whereas it is possible for a bad failing battery to cause computer problems in your car, this is generally not the case.

You are probably more likely to experience computer problems from loose or sparking battery connections or ECU/ECMs just failing.

You can confirm the cause of the computer problems by connecting a scanner to the ECU/ECM, reading and interpreting the underlying code, or by taking your car to an Autoparts store to have it done for you.

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