Heater Performance Test

Heater Performance Test

Before performing the following tests, check the engine coolant level and flow, engine coolant reserve/recovery system operation, accessory drive belt condition and tension, radiator air flow and cooling fan operation. Perform the A/C System Performance Test. Refer to => [ A/C Performance Test ] A/C Performance Test. If any DTCs are found in the HVAC control or the PCM, repair as necessary.


Do not remove radiator cap when engine is hot, personal injury can result.

If vehicle has been run recently, wait 15 minutes before removing the radiator cap. Place a rag over the cap and turn it to the first safety stop. Allow pressure to escape through the overflow tube. When the system pressure stabilizes, remove the cap completely.