INSPECTION PROCEDURE 12: The PTC heater does not work <Vehicles with PTC heater>.


COMMENTS ON TROUBLE SYMPTOM
With the engine and blower motor being operated, if the PTC heater does not operate by setting the heater control temperature to highest position at the coolant temperature of 77 °C or lower, the PTC heater, PTC heater relay, heater controller assembly (A/C-ECU) or its circuit system may be faulty.

PROBABLE CAUSES

  • Malfunction of the PTC heater
  • Malfunction of the PTC heater relay 1
  • Malfunction of the PTC heater relay 2
  • Malfunction of the PTC heater relay 3
  • Damaged the wiring harness or connectors
  • Malfunction of the heater controller assembly (A/C-ECU)
  • Malfunction of the engine-ECU

DIAGNOSIS PROCEDURE
1.Check the wiring harness between the heater controller assembly (A/C-ECU) connector terminal 9 and engine-ECU.
2.Check the trouble symptom procedures of engine-ECU (Refer to GROUP 13C - Inspection Procedure 27: PTC heater relay system )