High efficiency filters come with a cost besides $

P2002 - Diesel Particulate Filter Efficiency Below Threshold (Bank 1)
Description: The powertrain control module(PCM) monitors the efficiency of the diesel particulate filter for a concern. The efficiency of the filter is determined by the amount of restriction in the filter for a certain exhaust flow rate. The diesel particulate filter is preconditioned for 5,000 km (3,107 miles) before the PCM begins to monitor the level of restriction. The test fails when the measured level of restriction is less than the expected level calculated by the PCM. Possible Causes:

• Dirty air cleaner element
• Recent manual or thorough diesel particulate filter regeneration
• Aftermarket accessories and performance modifications
• Modified tailpipe
• Exhaust leaks before or near the diesel particulate filter pressure sensor
• Leaks in the diesel particulate filter pressure sensor connecting hose
• Damaged diesel particulate filter

Diagnostic Aids: Check for leaks in the exhaust system. Check for aftermarket exhaust accessories and performance modifications that decrease the exhaust restriction. If a new diesel particulate filter was recently installed, verify the diesel particulate filter parameter reset procedure was carried out.

Error Code:P2002
Description:
DTC P2002 Particulate Trap Efficiency Below Threshold (Bank1)
Possible solutions:
- Perform regeneration process. This process does not always solve the problem or the problem is solved for short term only.
- Remove/ Replace the Dust Particulate filter.
- Exhaust fuel addition INJECTOR ASSEMBLY. (Replace).
- Inspect turbo charger, in any.
- Mass Air Flow sensor.-
- Exhaust manifold convertor sub assembly

HEPA is a type of air purifier. It stands for high-efficiency particulate air. To qualify as a HEPA filter by government standards the filter must remove 99.7% of all particles larger than 0.3 micrometers from the air. The following site lists the top 10 HEPA purifiers available online - http://www.air-purifiers-america.com/AP101_top10.asp.

If you are using a pleated or high efficiency type filter, that is a problem, the high efficiency filters
actually restrict a great deal of airflow, a AC unit requires 500 cubic ft per minute of airflow per ton of refrigeration capacity, 500 sq ft of home per ton generally = 1500 sq ft home has a 3 ton unit or needs 1,500 cfm of airflow, both in heat and cool modes, Honeywelll Enalysises prove these filters even when new reduce up to 500 cfm of airflow, effectively making a 3 ton system a 2 ton in output due to airflow restriction, try removing that filter with the fan on, it likely is pulled in sold with a huge pressure drop caused by tj filters obstuctive flow capabilities.
And 755 of all A evaoprator coils have been plugged or restricted by dust , dirt, oils from cooking, cigarrettes, running with no filter etc, a chemical cleaning of the evap coil above the firnace, or brlow it is indicated as a possible issue. Use the cheap 99 cent seee through filters we used to use