Troubleshooting Catalyst Monitor Not Ready Issue In 7 Simple Steps

The OBDII (On Board Diagnostic) System regulates the vehicle’s performance with the help of monitors. Two types of monitors are present in our vehicles – continuous and non-continuous. Continuous monitors operate as long as the engine runs.

Whereas, non-continuous monitors need certain conditions like speed, ambient, acceleration, fuel level, and much more to carry out their testing process. Catalyst Monitors are non-continuous monitors that assess the ability of the catalytic converter to decrease harmful emissions.

But, what if your vehicle indicates ‘catalyst monitor not ready’? So, let’s explore further how to make your vehicle’s catalyst monitor ready!

What Are The Symptoms Of Bad Catalyst Monitor?

catalyst monitoring
A loud, rattling sound from under the car is another symptom of a damaged catalyst monitoring (Photo:

Loss of engine efficiency

One of the first symptoms often associated with a faulty or damaged catalytic monitor is reduced engine efficiency. The catalytic converter is integrated into the vehicle’s exhaust system, and as such, can affect the engine’s performance if it develops any problems. A clogged converter will restrict exhaust air flow, while a cracked converter will leak harmful emissions. Either fault can negatively affect engine performance and reduce power and acceleration as well as fuel economy.

Strange noise

A loud, rattling sound from under the car is another symptom of a damaged catalytic monitor. If a catalytic converter becomes old or has internal damage from excessively rich fuel mixtures, the honeycomb grids coated with the catalyst on the inside of the converter can be damaged, causing a loud sound. The sound may be more obvious when starting the vehicle and will worsen over time.

Check engine light comes on

A damaged catalytic converter can also cause the check engine light to come on. Oxygen sensors and air-fuel ratio sensors in modern vehicles monitor the efficiency of the catalytic converter by monitoring the fuel level in the exhaust. If the ECU detects that the catalytic converter is not working correctly or not catalyzing the emissions properly, it will turn on the check engine light to alert the driver of the problem. A variety of other problems can trigger the check engine light, so it’s a good idea to scan your vehicle for trouble codes to be sure of the problem.

7 Steps to Follow When Catalyst Monitor Not Ready

The output of the catalyst monitor can be either ‘not ready’ or ‘ready.’ If the output of the monitor is not ready, what does that indicate? It signifies that the requisite Drive Cycle has not run completely; thus, the catalyst monitor has not tested the catalytic converter.

So, in order to make the status of the catalyst monitor ‘ready’, you need to follow these simple steps.

1. Make sure the engine light is off

The first and foremost step is to check whether the engine light is off. If your vehicle has active trouble codes, it may stop a monitor from running completely.

2. Check if your vehicle has a coolant temperature

The drive cycle starts with a cold start. The engine coolant temperature of your vehicle should be below 50°C (122°F) and within 6°C (11°F) of the air temperature. You can achieve this by allowing your car to sit overnight.

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3. Let the engine be idle for 2 minutes

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Make the speed of your vehicle fall gradually up to 32 km/hr (20 MPH) (Photo: )

The next step is to start the engine and keep it idle for two and a half minutes, keeping the rear defroster and AC on.

4. Drive the vehicle at a steady speed of 55 MPH

Now, switch the rear defroster and ac off and keep the speed of your vehicle at 90 km/hr (55MPH) nearly for 3 minutes. During this period, the purge and Fuel monitor diagnostics will take place.

5. Decelerate your vehicle’s speed at 20 MPH

Make the speed of your vehicle fall gradually up to 32 km/hr (20 MPH). Avoid touching/shifting of clutch or brake.

6. Again speed up

Drive your vehicle back to 55MPH (90 km/hr) at 3/4 throttle for nearly five minutes. The catalyst monitor diagnostics will take place during this period. If the battery is detached or the catalyst is not ready, it might take five complete driving cycles to decide the status of the catalyst. For additional information about catalyst monitors, one can refer to maintenance tips by car experts.

7. Stop the vehicle

Now, make your vehicle slow down and allow it to sit idle for 2 minutes.

That’s all. By practicing the above-mentioned steps carefully, you can easily troubleshoot the problem of ‘catalyst monitor not ready.’ Next time your vehicle shows such kind of signals; don’t forget to follow these steps.

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