Tech Tips
Use the table below to help determine the causes of the problem symptom. The potential causes of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.
Inspect the fuses and relays related to this system before inspecting the suspected areas below.
| Symptom | Suspected Area | See page |
|---|---|---|
| All functions of the heater system do not operate. | IG power source circuit* | |
| Air conditioning amplifier assembly | ||
| Air Flow Control: No blower operation. | Blower motor circuit | |
| Air conditioning amplifier assembly | ||
| Air Flow Control: No blower control. | Blower motor circuit | |
| Air conditioning amplifier assembly | ||
| Air Flow Control: Insufficient air flow. | Blower motor circuit | |
| Air conditioning amplifier assembly | ||
| Temperature Control: No warm air comes out. | Engine coolant temperature sensor circuit (for 1ND-TV)* | |
| Engine coolant temperature sensor circuit (for 1NR-FE)* | ||
| Engine coolant temperature sensor circuit (for 1NZ-FE)* | ||
| Ambient temperature sensor circuit* | ||
| CAN communication system* | ||
| PTC heater circuit* | ||
| No. 3 heater control (Max hot switch)* | - | |
| Air mix damper control cable | - | |
| Air conditioning amplifier assembly | ||
| ECM (for 1ND-TV)* | ||
| ECM (for 1NR-FE)* | ||
| ECM (for 1NZ-FE)* | ||
| Harness or connector | - | |
| Temperature Control: Output air is warmer than the set temperature or response is slow. | Engine coolant temperature sensor circuit (for 1ND-TV)* | |
| Engine coolant temperature sensor circuit (for 1NR-FE)* | ||
| Engine coolant temperature sensor circuit (for 1NZ-FE)* | ||
| Ambient temperature sensor circuit* | ||
| CAN communication system* | ||
| Air mix damper control cable | - | |
| Radiator unit sub-assembly | - | |
| Air conditioning amplifier assembly | ||
| ECM (for 1ND-TV)* | ||
| ECM (for 1NR-FE)* | ||
| ECM (for 1NZ-FE)* | ||
| Temperature Control: No temperature control (only Max. hot) | Engine coolant temperature sensor circuit (for 1ND-TV)* | |
| Engine coolant temperature sensor circuit (for 1NR-FE)* | ||
| Engine coolant temperature sensor circuit (for 1NZ-FE)* | ||
| CAN communication system* | ||
| Air mix damper control cable | - | |
| Air conditioning amplifier assembly | ||
| ECM (for 1ND-TV)* | ||
| ECM (for 1NR-FE)* | ||
| ECM (for 1NZ-FE)* | ||
| No air inlet control. | Air inlet damper control cable | - |
| No air flow mode control. | Defroster damper control cable | - |
| Engine idle speed increase does not occur, or is continuous* | Air conditioning amplifier assembly | |
| ECM (for 1ND-TV)* | ||
| ECM (for 1NR-FE)* | ||
| ECM (for 1NZ-FE)* | ||
| CAN communication system* |
*: w/ Quick Heater Assembly