Kia Rio YB Quiz
Heating, Ventilation, and Air Conditioning

PTC Heater

In this manual: Heating, Ventilation, and Air Conditioning
General Information — 8Maintenance — 31Engine Mechanical System — 44Engine Electrical System — 14Emission Control System — 9Engine Control System/Fuel System — 30Clutch System — 10Manual Transmission — 10Automatic Transmission — 23Drive Shaft and Axle — 8Suspension System — 15Steering — 9Restraints — 14Brake System — 22Body (Interior and Exterior) — 115Body Electrical System — 84Heating, Ventilation, and Air Conditioning — 28
15steps
~90min
4/5difficulty
Done 0 of 15

Description and Operation

Description

The PTC (Positive Temperature Coefficient) heater is installed at the outlet or rear side of the heater core.

The PTC heater is an electric heater that uses a PTC element as an auxiliary heating device to compensate for the lack of internal heat source in a high-efficiency diesel engine. The electric heater heats the interior by directly heating the air passing through the heater core. The name itself implies that the element has a resistance that changes proportionally with temperature.

Operating Principle

The ECM outputs the PTC ON signal and turns on PTC relay 1. Then the heater controller turns on PTC relay 2 and PTC relay 3 at 15-second intervals.

However, PTC relay 3 may operate when the battery voltage is above 12.4 V.

Operating Condition

The PTC heater operates under the following conditions:

  • Battery voltage: 12 V or higher

  • Engine is running

  • Ambient Temperature and Coolant Temperature

Ambient Temperature Engine Coolant Temperature PTC Operation
Below -10°C (14°F) Below 80 °C ON
15°C (59°F) Below 70 °C ON
20 °C or higher - OFF
- 80 °C or higher OFF

Repair Procedures

Inspection

Operation Logic Check

Check PTC operation using the confirmation logic as follows:

  1. Input

    1. Set the Vent, Bi-Level or Floor mode and the maximum heat position.

    2. Turn the blower switch off.

    3. Press the intake (recirculation) button 5 or more times.

    4. All button indicators blink continuously at 0.5-second intervals (MANUAL).

      The entire LCD graphics turn on and off continuously at 0.5-second intervals (FATC).

    5. Confirm PTC operation by turning on the blower switch.

    6. Each PTC relay activates at 3-second intervals.

    7. The logic test will be automatically canceled after 30 seconds.

      It can also be canceled as follows:

      • Using any switch other than the fan, temperature and mode switches

      • Ignition switch OFF.

  2. Cancel

    • Operate any switch other than the fan, temperature control, or mode switch.

    • Turn the ignition off.

    • The test is automatically cancelled after 30 seconds.

  3. If the PTC does not operate, replace the PTC heater with a known good one and check operation.

    If the problem is corrected, replace the PTC heater.

Operation Test

This test must be performed with the PTC on.

  1. Start the engine.

  2. Check the current in the wiring using a clamp-type multimeter.

    Pattern Current (A)
    PTC 1 ON 0,1 ~ 33
    PTC 2 ON 0,1 ~ 33
    PTC 3 ON 0,1 ~ 33
    General 0,1 ~ 100

  3. If the current does not meet the specification, check the related wiring.

Resistance Test

  1. Turn the ignition off.

  2. Disconnect the PTC heater connector.

  3. Measure the resistance between terminals 1, 2, 3 of the PTC heater and ground.

    Resistance: 0.3 - 1.5 ohms

    1. PTC 1

    2. PTC 2

    3. PTC 3

  4. If the measured resistance does not meet the specification, replace the PTC heater with a new one.

Replacement

  1. Disconnect the negative (-) battery terminal.

  2. Remove the console assembly.

    (Refer to Body - Floor Console Assembly)

  3. Disconnect the PTC heater connector (A).

  4. Remove the PTC heater core (A) after loosening the PTC heater mounting screws.

  5. Installation is the reverse of removal.

Test yourself

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