Inspection Procedure 8: The PTC heater does not work <Russia>

COMMENTS ON TROUBLE SYMPTOM
When the PTC heater does not work under the following conditions, the heater switch system or the PTC heater circuit system may be defective.
PTC heater operating conditions
  • heater switch: ON
  • Air outlet: FOOT/DEF, FOOT, FACE/FOOT
  • Temperature control dial: MAX HOT
  • Coolant temperature: 80 degrees celsius or less
note When the coolant temperature becomes above 80 degrees celsius and PTC heater stops the operation, the PTC heater does not operate until coolant temperature becomes below 70 degrees celsius.

PROBABLE CAUSES

  • Malfunction of the heater switch system
  • Damaged the wiring harness or connectors
  • Malfunction of the PTC heater relay 1
  • Malfunction of the PTC heater relay 2
  • Malfunction of the PTC heater 1
  • Malfunction of the PTC heater 2

DIAGNOSIS PROCEDURE

STEP 1. Connector check: C-149 PTC heater 1 connector

Q. Is the check result normal?

Go to Step 2.

Repair the connector.

STEP 2. Resistance measurement at the C-149 PTC heater 1 connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Continuity between terminal 1 and body earth
OK: Continuity (Less than 2Ω)

Q. Is the check result normal?

Go to Step 4.

Go to Step 3.

STEP 3. Check the wiring harness between C-149 PTC heater 1 connector terminal No.1 and body earth.


  • Check the PTC heater earth line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction .)

Repair the wiring harness.

STEP 4. Resistance measurement at the C-150 PTC heater 2 connector.

(1)Disconnect the connector, and measure at the wiring harness side.

(2)Continuity between terminal 1 and body earth
OK: Continuity (Less than 2Ω)

Q. Is the check result normal?

Go to Step 6.

Go to Step 5.

STEP 5. Check the wiring harness between C-150 PTC heater 2 connector terminal No.1 and body earth.


  • Check the PTC heater earth line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction .)

Repair the wiring harness.

STEP 6. Connector check: C-105 engine-ECU connector

Q. Is the check result normal?

Go to Step 7.

Repair the connector.

STEP 7. Voltage measurement at C-149 PTC heater 1 connector.

(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the "ON" position.


(3)Disconnect engine-ECU connector C-105 and earth terminal 36.

(4)Voltage between terminal 2 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 16.

Go to Step 8.

STEP 8. Connector check: A-140X PTC heater relay 1 controller connector

Q. Is the check result normal?

Go to Step 9.

Repair the connector.

STEP 9. Check the PTC heater relay 1 continuity.
Refer to .

Q. Is the PTC heater relay 1 in good condition?
Go to Step 10.
Replace the PTC heater relay 1.

STEP 10. Voltage measurement at A-140X PTC heater relay 1 connector.

(1)Remove the relay, and measure at the relay block side.
(2)Turn the ignition switch to the "ON" position.

(3)Voltage between terminal 3 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 12.

Go to Step 11.

STEP 11. Check the wiring harness between A-140X PTC heater relay 1 connector terminal No.3 and the ignition switch (IG2).




note Prior to the wiring harness inspection, check intermediate connectors C-148, A-28 and junction block connector C-210,C-207 and repair if necessary.

  • Check the PTC heater relay 1 earth supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction .)

Repair the wiring harness.

STEP 12. Voltage measurement at C-140X PTC heater relay 1 connector.

(1)Remove the relay, and measure at the relay block side.

(2)Voltage between terminal 2 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 14.

Go to Step 13.

STEP 13. Check the wiring harness between A-140X PTC heater relay 1 connector terminal No.2 and the fusible link (25).


  • Check the PTC heater relay 1 power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 14. Check the wiring harness between A-140X PTC heater relay 1 connector terminal No.1 and C-105 engine-ECU connector terminal No.38.


note Prior to the wiring harness inspection, check intermediate connector C-148, and repair if necessary.

  • Check the PTC heater relay 1 earth line for open and short circuit.

Q. Is the check result normal?

Go to Step 15.

Repair the wiring harness.

STEP 15. Check the wiring harness between A-140X PTC heater relay 1 connector terminal No.4 and C-149 PTC heater connector terminal No.2.



  • Check the PTC heater relay 1 power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 16. Voltage measurement at C-150 PTC heater 2 connector.

(1)Disconnect the connector, and measure at the wiring harness side.
(2)Turn the ignition switch to the "ON" position.

(3)Disconnect engine-ECU connector C-105 and earth terminal 41.

(4)Voltage between terminal 2 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 25.

Go to Step 17.

STEP 17. Connector check: A-141X PTC heater relay 2 controller connector

Q. Is the check result normal?

Go to Step 18.

Repair the connector.

STEP 18. Check the PTC heater relay 2 continuity.
Refer to .

Q. Is the PTC heater relay 2 in good condition?
Go to Step 19.
Replace the PTC heater relay 2.

STEP 19. Voltage measurement at A-141X PTC heater relay 2 connector.

(1)Remove the relay, and measure at the relay block side.
(2)Turn the ignition switch to the "ON" position.

(3)Voltage between terminal 3 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 21.

Go to Step 20.

STEP 20. Check the wiring harness between A-141X PTC heater relay 2 connector terminal No.3 and the ignition switch (IG2).




note Prior to the wiring harness inspection, check junction block connectors C-207 and C-210, intermediate connector A-28 and C-148, and repair if necessary.

  • Check the PTC heater relay 2 power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction .)

Repair the wiring harness.

STEP 21. Voltage measurement at A-141X PTC heater relay 2 connector.

(1)Remove the relay, and measure at the relay block side.

(2)Voltage between terminal 2 and body earth.
OK: System voltage

Q. Is the check result normal?

Go to Step 23.

Go to Step 22.

STEP 22. Check the wiring harness between A-141X PTC heater relay 2 connector terminal No.2 and the fusible link (25).


  • Check the PTC heater relay 2 power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction ).

Repair the wiring harness.

STEP 23. Check the wiring harness between A-141X PTC heater relay 2 connector terminal No.1 and C-105 engine-ECU connector terminal No.41.


note Prior to the wiring harness inspection, check intermediate connector C-148, and repair if necessary.

  • Check the PTC heater relay 2 earth line for open and short circuit.

Q. Is the check result normal?

Go to Step 24.

Repair the wiring harness.

STEP 24. Check the wiring harness between A-141X PTC heater relay 2 connector terminal No.4 and C-150 PTC heater connector terminal No.2.



  • Check the PTC heater power supply line for open circuit.

Q. Is the check result normal?

The trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope with Intermittent Malfunction .)

Repair the wiring harness.

STEP 25. Connector check: C-43 A/C-ECU connector

Q. Is the check result normal?

Go to Step 26.

Repair the connector.

STEP 26. Check the wiring harness between C-43 A/C-ECU connector terminal No.15 and C-105 engine-ECU connector terminal No.35.



note Prior to the wiring harness inspection, check intermediate connector C-52, and repair if necessary.

  • Check the A/C-ECU input line for open and short circuit.

Q. Is the check result normal?

Go to Step 27.

Repair the wiring harness.

STEP 27. Replace the A/C-ECU, and then recheck the trouble symptom
Check that the PTC heater works normally.

Q. Is the check result normal?
This diagnosis is complete.
Replace the engine-ECU.