Using OBD2 port adapter to check air conditioning

[MrFixit]

@ajzwilli

I added your measurement to the plot -
https://docs.google.com/spreadsheet...p6pGo8m97MPip9s97kPDQMqw4/edit#gid=2093521734

Indeed, your static pressure looks 'nominal'

It will be important in your case to measure the condition while operating. This A/C pressure is available in the AP200. It is located in the 'PGM-FI' Control Unit as Item #59. It is labeled "A/C Pressure Sensor". The readout is in kPa so it needs to be converted to psi.

The air temperature inside and outside the vehicle appear in the "Electric Powertrain" section of the AP200 as the 2nd and 3rd parameters (they are in Degrees C).

When you get your Vgate, this is easier because there is a dashboard with just these 3 parameters on the screen.

Keep in mind that you can have a "normal" static pressure even if your Freon is low. When you try to operate however, the little bit of Freon can all evaporate and you will have no cooling.

 

[ajzwilli]

@ajzwilli

I added your measurement to the plot -
https://docs.google.com/spreadsheet...p6pGo8m97MPip9s97kPDQMqw4/edit#gid=2093521734

Thank you for the AP200 instructions. I added the following from the test this morning:
Static:
Temp 74 F
Pressure 80.35 psi

Operating:
Went as high as 126.9 psi, but then dropped and stabilized around 114 psi after about 5 minutes
Temp 79F Inside, 73 Outside (instrument panel said 80 / 81) during this time. Car was parked in garage and had not been driven, so I would have expected all temps to be close together.

Looks like I've got something else going on - still no cold air when operating

 

[MrFixit]

@ajzwilli ,
Your readings seem to indicate you should have some cooling.
Obviously there is more to learn about how to interpret all of this.
It will be interesting to learn what your problem is, and maybe get some new readings once it is repaired.

 

[Danks]

Thank you for the AP200 instructions. I added the following from the test this morning:
Static:
Temp 74 F
Pressure 80.35 psi

Operating:
Went as high as 126.9 psi, but then dropped and stabilized around 114 psi after about 5 minutes
Temp 79F Inside, 73 Outside (instrument panel said 80 / 81) during this time. Car was parked in garage and had not been driven, so I would have expected all temps to be close together.

Looks like I've got something else going on - still no cold air when operating

A couple of things to check. Does your AC compressor run? Have you checked your cabin air filter?

 

[MrFixit]

A couple of things to check. Does your AC compressor run? Have you checked your cabin air filter?

I think the pressure that @ajzwilli measured (127 -> 114) demonstrates that his compressor is 'running'... I'm not sure how else you could determine whether it is running because there is no visible drive belt / clutch like in the old-fashioned vehicles.

The cabin filter is certainly a good thought, and worth checking. If you don't know how to do it, there is a thread here with a link to a video that shows you how.
If I can find it here:
https://www.insideevsforum.com/comm...e-clarity-maintenance-minder.8189/#post-96939

 

[ajzwilli]

I couldn't get into my dealership for a couple weeks. In the meantime, the MM from my AP200 indicates a filter change is approaching, so I'll get it changed to rule that issue out (I have strong airflow from the vents).

 

[MrFixit]

so I'll get it changed to rule that issue out (I have strong airflow from the vents).

I believe the thought wasn't just routine maintenance for the filter... There could be a mouse / rodent nest in there blocking air flow (this is a favorite spot for the little buggers). If you have good air flow, this is a long shot but I am not certain about how the ducting works. Could it be that a clogged filter would block the path to the A/C evaporator while still allowing air flow through the vents?

 

[ajzwilli]

Filter was relatively clean, replaced, still no cold air. Appreciate the suggestions, I'll keep trying them up to my service appointment.

 

[MrFixit]

Filter was relatively clean, replaced, still no cold air. Appreciate the suggestions, I'll keep trying them up to my service appointment.

This Document (from the Honda Service Manual) was posted quite a while back... It does not contain detailed diagnostic procedures, but has a good description of the A/C system with some diagrams, and seems relevant to this thread...

 

[MrFixit]

Important - See this post regarding a warranty extension:
https://www.insideevsforum.com/comm.../clarity-a-c-problem.6302/page-10#post-134014

 

[sabasc]

Weak compressor? Damaged from running with no refrigerant? Warranty item?

Hi everyone, I have added data points from July 5th and July 8th. The temperature is falling very slowly and this is with the car not in the sun. Pressure seem to be well within local ranges for static and operating PSI.

 

[coutinpe]

From the land of the hot air I just added my data I collected this morning (when taking off and after my return from a morning errand) to @MrFixit's spreadsheet. As a side note, I noticed at the beginning a wild disparity between the outside temperature shown in the instrument cluster and whatever the OBDII scanner was reading (ex. 96F cluster panel vs 89.6 ODBII), but it converged after a while. I also noticed (as sabasc) that the temperature falls too slowly. I set the thermostat at 75, but after a 10 minute drive it never fell below 89, notwithstanding I could feel cooler air flowing from the vents. I wonder where the temp sensors are and why seems to be a different one for the instrument cluster reader and another for the ODBII scanner. I will add more date on the following days, when temperatures will be awfully higher and I will have to do a longer drive. I'll also try to figure out the time course of the cabin cooling.

 

[pigrew]

The service manual also contains expected pressures. Perhaps these could be correlated with the scan tool readings.

Conditions:

The blower intake temperature must be at least 68 °F (20 °C).

1. Move the vehicle out of direct sunlight and let it cool down to the surrounding (ambient) temperature. If necessary, wash the vehicle to cool it down more quickly
2. Open the hood.
3. Open the front doors.
4. Apply the parking brake.
5. Remove glove box.
6. Shift the gear position to the P position/mode.
7. Turn the vehicle to the READY TO DRIVE mode.
8. Set the A/C system to the following conditions.
9. A/C: ON
10. Temperature control: MAX COOL (Lo)
11. Mode control: VENT
12. Recirculation control: RECIRCULATE
13. Fan control: Max
14. All vents: Open
15. No driver or passengers in the vehicle.
16. Wait 10 minutes for readings to stabalize.