Denso Air Conditioner Error Code HP

The HP code indicates the high pressure switch has activated, meaning refrigerant pressure on the high side of the system reached an unsafe level and the safety circuit shut the compressor down. A blinking HP light means the switch has tripped 3 times within 24 hours. A solid HP light means it has tripped 10 times within 24 hours, indicating a persistent problem that requires diagnosis.

No. The high pressure switch is a safety device designed to protect the compressor and refrigerant circuit from damage caused by excessive pressure. Continuing to operate the system while repeatedly triggering this switch risks compressor failure, refrigerant line damage, or fitting failures. The system should be diagnosed and repaired before returning it to regular use, especially if the HP light is solid.

No, a reset clears the fault indicator but does not correct whatever is causing the high pressure condition. If the underlying cause is still present, the high pressure switch will continue to activate and the HP code will return. The reset should be performed only after completing diagnosis and correcting the root cause, following the troubleshooting process outlined in the Denso documentation.

Yes, the reset procedure requires holding the SET TEMP UP and DOWN buttons simultaneously for 3 seconds. However, resetting the code without identifying and correcting the root cause will allow the fault counter to accumulate again, and the system will return to a fault state. A reset is only useful after the underlying issue, such as a dirty condenser or refrigerant problem, has been resolved.

Repair costs depend heavily on the root cause. Condenser cleaning is typically low cost, in the range of $75 to $150 for a service call. Refrigerant recovery and recharge due to overcharge or contamination generally runs $150 to $400. A condenser fan motor replacement may cost $200 to $500 including labor. A compressor replacement, if high pressure damage has already occurred, can reach $800 to $2,000 or more.