For the most part, yes. It's hard to say conclusively without checking the high side pressure as well with a full manifold gauge set.

However, you should also be checking out the sight glass. If there are no bubbles, you're not low.

 

I didn't see the the sight glass. Where is it located?
Here are pictures of my high pressure port and I don't see a sight glass close to it.
Also, yesterday, the malfunction indicator lamp came up (see second picture). Could it have something to do with the fact that some refrigerant was sprayed on the engine when the hose was not well screwed? I wiped most of the drops but not everywhere.

 

Hmm... mine was right by the high pressure switch visible in your picture. Wonder if it was just the 06?

Get your codes checked.

 

I checked the code and it indicated a problem with the catalytic converter. I cleared the fault, drove about 10 miles, did the diagnostic again, and there was no fault. Am I OK?

 

Note that I indicated you should get your codes checked. "a problem with the catalytic converter" is not a code. There are two cats in the car and different codes mean different things.

Was it P0420?

If so, your upper cat is failing. If emissions are required in your area, you'll likely need to do something about it. You can try an anti-fouler on the downstream O2 sensor, or you can replace the upper cat with an aftermarket.

In extremely rare cases, O2 sensors can be the cause, but they will usually throw codes specific to the O2 sensors themselves.

Lastly, if your car is burning oil, that contributes to cat failure and can eventually plug them.

 

Yes, it was P0420. I used the Torque app, which sent me to this link: https://www.troublecodes.net/pcodes/p0420/
Towards the bottom, there is the section "How do you troubleshoot P0420?", and in step 2, it says: "If no additional codes are present, clear code P0420, and operate the vehicle normally for a few miles to allow the PCM to enter closed loop operation, before scanning the system again to see if the code returns.".
I had no additional code, and the code didn't return.

 

P0420 usually returns. It's an indication that the cat is performing below the efficiency threshold. It's possible there was a combination of related factors that triggered it, but they usually come back.

Hopefully, I'm wrong. I had to replace one of the cats in one of my '06s. Wasn't that hard to do, but I ended up spending a lot of money on that car.

 

OK, I'll check again in 1 week. Now, the AC is not cold anymore, after the refrigerant leak when I wanted to measure the pressure. I was thinking, maybe I should reproduce another of this leak to remove more of the old refrigerant before adding new refrigerant?

 

The only reason to remove the old refrigerant is if it's contaminated. Refrigerant does not break down or degrade UNLESS it's contaminated. If it's contaminated, you should punt and go to a Honda dealership for evac and recharge.

Note that it is illegal to deliberately vent R-134a.

 

I had to unplug the battery. P0420 came back. Emissions are not required in my area, should I still do something about it?