BMW Catalyst Monitor Not Ready: Causes And Solutions

Is your BMW Catalyst monitor not ready for a while without you knowing why?

How do I get my catalyst monitor ready? Don’t rush to worry! Many fellow drivers have also been in that situation before!

We may already learn that the catalytic converter’s main usage is to aid in degrading the car’s hazardous pollutants by employing oxygen.

But how can we know whether this component is operating properly? 

Wait no longer but dive right in and get yourself the best answer!

What Are The Causes Of BMW Catalyst Monitor Not Ready?

bmw catalyst monitor not ready
Why Is BMW Catalyst Monitor Not Ready

Why is the BMW catalytic converter monitor not ready?

Most of the time, the reason to blame is that the catalytic monitor has not yet been triggered, the stored codes are removed, or the cell sensors are loose.

Also, the performance tuning tasks or using a simulator can impair the monitor.

It’s actually a much more complicated procedure where the PCM and numerous other factors activate your catalytic monitor.

Without these components performing their tasks, cat not ready code will be the signal you would see appear on the monitor all the time.

The Stored Codes Have Been Removed

As aforementioned, the PCM plays a vital role in causing the Catalyst monitor not to work. Yet, how come that happened?

Let’s first court about troubleshooting codes, including five digits known as fault codes in the PCM.

This code will assist in locating certain kinds of issues which occur in your converter and enabling the appropriate monitor to solve the problem.

The diagnostic trouble codes can also be tracked using an OBDII scanner, a particular device that may remove them as easily as it monitors them.

However, this is usually where the trouble initiates itself. Since the code gets erased, the PCM data must start counting from the beginning to stimulate the monitoring systems in your automobile.

It goes without saying that the job will take a while before the monitor can be triggered.

That explains the reason why it keeps presenting as catalytic not ready no matter how many times you refire the engine.

Using A Simulator

Many had no idea about this, but to activate the converter monitor and the PCM, you must first reach a particular set of normal driving metrics.

Doing so will cost you a certain while, so several others shall opt for another alternative, which is employing a simulator as a shortcut.

Unfortunately, there is indeed a noticeable risk you would have to take when using this timesaving method.

As such, all of the monitors (even your converter one) will be turned off immediately if the PCM can identify any sort of deceptive change as it’s processing the data.

Performance Tuners

To put it simply, performance tuners are what vehicle manufacturers install in your car to improve its performance.

This tuning task will call for some changes in the internal programming structure of the car.

It may sound irrelevant, but yes, such a process shall affect your automobile’s monitor system in one way or another, possibly resulting in less effective execution.

Loose Cell Sensors

The loose or disconnected cell sensors should be another leading factor to check when it comes to your BMW catalyst monitor not being ready.

The reason is that once these heated oxygen sensors or the O2 sensor wrench get detached, the PCM’s memory will have no other way rather than resetting itself.

As a result, without them processing, there shall be nothing that can activate the catalytic monitor, which was originally the job of the metrics displayed by the PCM.

How To Get Catalyst Monitor Ready

smog check catalyst not ready
Way To Obtain Catalyst Monitor Ready

How do you fix a catalyst not ready? Just a few simple steps in assistance, and there you go all the way! 

Step 1: Turn Off The Check Engine Light.

Checking to see if the engine light is off is the first and most important step that you should get done in how to fix OBD2 not ready.

Sometimes, the blown fuse is to blame for the OBD2’s failure, so check it too.

Otherwise, the EVAP monitor may not function at all as there have been such active trouble codes in your vehicle’s system, hence the catalyst and evap system not ready problem.

Step 2: Verify Whether Your Car Features An Engine Coolant Temperature

Since every car requires a cold start to ignite its  generic drive cycle, it is vastly important to make sure your vehicle has an appropriate ambient air temperature.

That means you should go for the range of below 122°F (50°C) but still differentiating only 11°F (6°C) compared to the temperature of the air outside.

All you have to do is let the machine stay idle overnight, and there you have such a target achieved easily!

Step 3: Leave The Engine For Two Minutes To Idle.

After the check goes well with the engine light and the temperature, it’s time for you to fire up the engine in drive and idle it for at least 2 minutes.

While doing so, remember to also turn on the AC and keep the rear defrost.

Step 4: Keep The Car Moving With A Stable Speed At 55 MPH

Once it’s time out for idling, you can start your driving procedure then. However, steady speed is also an inevitable factor in the process.

Not just any steady speed can work out with this troubleshooting, but you will need the exact 55 MPH (90km/hr) within 3 minutes running to activate the energy monitor diagnostics and purge.

Bear in mind to only carry out this task at places where you would not get some outstanding speeding tickets.

Step 5: Reduce The Speed Of Your Car To 20 MPH

That would be enough with the acceleration. Now, decelerate the pace until it reaches 20 MPH (32 km/h). This should stay out of the leagues of the accelerator pedal, brake or clutch.

Otherwise, all these steps done above would be in absolutely vain.

Step 6: Regain A Speed Of 55 MPH

Accelerate the vehicle one more time with a speed of 90 km/h (55 MPH) for approximately 5 minutes.

The diagnostics system on your catalyst disabled monitor should function properly during this time.

It may take five full drive cycles to determine the Catalyst’s readiness monitor if the battery is disconnected as the Catalyst is not yet ready.

Refer to maintenance advice from auto professionals for further information about catalyst incomplete monitors.

What Indicates a Malfunctioning Catalytic Converter?

how to get catalyst monitor ready
Malfunctioning Catalytic Converter

There are nearly always obvious symptoms to tell whether your automobile features a damaged automotive component. Things are no exception with the catalytic converter.

Greater Emission

We have gone through this before: Since the emission systems are indeed what your catalytic converter is designed to work with, no trace of decreased emission will ironically be the most concrete drive trace of a failing converter.

So whenever you sense even just a little increase in the emission inspection, take it as a sign implying that there are many chances the catalytic converter may have got blocked.

Fuel Vapor

The fuel consumption of the automobile will also get impacted by a struggle with the catalytic converter.

As such, if you see a cloud of gasoline vapor when taking the carburetor lid off the vehicle (which properly will require you to rev the engine first to be able to conduct), the possibility of your converter getting blocked may stand firmly at the highest rates.

Performance Reduction

It goes without saying that the engine control units can no way operate at their best when there are problems with the converter.

To give further explanation for this, you have to acknowledge that as the converter falls to carry on its job, pressure will frequently build up in the rear of that component, lowering engine power.

Power Loss

Another indicator of the cat monitor not ready that you should not neglect is the drivetrain losing power when going down or up a slope.

This is because the emission cannot get out of the vehicle adequately due to the catalytic converter getting clogged, forcing it to consume more power to perform the assigned task of accelerating and decelerating.

Both complete and partial blockage can be to blame for this degradation.

Engine Misfiring

This is one of the most frequent faults during operation that is commonly linked to the failure of other components.

You can check to see if the oil has gotten into the converter or if the converter overheated during the car’s start-up.

If that’s the case, it may be time to take your broken vehicle to the nearest garage or inspection station for decent repair or substitution.


That’s all about our analysis of the BMW catalyst monitor not ready problem.

Although this issue is prevalent, many individuals mistakenly believe that the converter is to blame, while the truth is totally another prospect.

Trust us, many may have fallen into that trap of misunderstanding.

That’s why we are here, hoping to help you with the clearest provision of causes as well as the most easy-to-approach solutions to such a botheration.

Now you’ve known the way to get out of this, it’s time to get some practice! Good luck to you then!

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