Some customers may complain about poor heater performance even after the engine reaches normal operating temperature. This may be caused by a clogged heater unit. For Mazda6 and CX-5, the check engine light may illuminate with the DTC P011A:00 stored at the same time. P011A:00 ECT sensor No.1/No.2 performance problem. NOTE: Refer to TSB 01-015/15 if the customer is using a block heater at temperatures below freezing.
