Inspection Procedure
18: The PTC heater (Driver’s side) does not work
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COMMENTS ON TROUBLE SYMPTOM
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When the PTC heater does not work under the
following conditions, the PTC heater circuit
system may be defective.
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PTC heater operating conditions
- Air outlet: FOOT/DEF, FOOT, FACE/FOOT
- Temperature control dial: MAX HOT
- Coolant temperature: 82 degrees Celsius or less
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note |
When the coolant temperature becomes above 82
degrees Celsius and PTC heater stops the
operation, the PTC heater does not operate until coolant temperature
becomes below 72 degrees
Celsius.
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- Damaged the wiring harness or connectors
- Malfunction of the PTC heater relay 1
- Malfunction of the PTC heater 1
- Malfunction of the automatic A/C control panel
(A/C-ECU)
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STEP 1. Connector check: D-128 PTC heater 1 connector
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Q.
Is the check result normal?
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Go to Step 2.
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Repair
the connector.
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STEP 2. Resistance measurement at the D-128 PTC heater
connector.
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(1)Disconnect the connector, and measure at the wiring
harness side.
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(2)Continuity between terminal 1 and body
earth OK: Continuity (Less than 2 Ω)
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Q.
Is the check result normal?
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Go to Step 4.
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Go to Step 3.
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STEP 3. Check the wiring harness between D-128 PTC heater 1 connector
terminal No.1 and body earth.
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- Check the PTC heater 1 earth line for open circuit.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope
with Intermittent Malfunction ).
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Repair
the wiring harness.
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STEP 4. Connector check: D-213 engine-ECU connector
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Q.
Is the check result normal?
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Go to Step 5.
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Repair
the connector.
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STEP 5. Voltage measurement at D-128 PTC heater
connector.
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(1)Disconnect the connector, and measure at the wiring
harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Disconnect engine-ECU connector D-213 and earth terminal
41.
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(4)Voltage between terminal 2 and body
earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 14.
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Go to Step 6.
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STEP 6. Connector check: A-46 PTC heater relay 1
connector
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Q.
Is the check result normal?
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Go to Step 7.
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Repair
the connector.
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STEP 7. Check the PTC heater relay 1 continuity.
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Refer to .
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Q.
Is the PTC heater switch relay 1 in good condition?
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Go to Step 8.
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Replace the PTC heater relay
1.
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STEP 8. Voltage measurement at A-46 PTC heater relay 1
connector.
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(1)Remove the relay, and measure at the relay block
side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal 1 and body
earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 10.
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Go to Step 9.
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STEP 9. Check the wiring harness between A-46 PTC heater relay 1
connector
terminal No.1 and the ignition switch (IG2).
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note |
Prior to the wiring harness inspection, check
junction block connectors D-403, D-401,
joint connector A-15 and intermediate connector D-241, and repair if
necessary.
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- Check the PTC heater relay 1 earth supply line for open
circuit.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope
with Intermittent Malfunction ).
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Repair
the wiring harness.
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STEP 10. Voltage measurement at A-46 PTC heater relay 1
connector.
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(1)Remove the relay, and measure at the relay block
side.
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(2)Voltage between terminal 5 and body
earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 12.
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Go to Step 11.
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STEP 11. Check the wiring harness between A-46 PTC heater relay 1
connector terminal No.5 and the fusible link (30).
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- Check the PTC heater relay 1 power supply line for open
circuit.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope
with Intermittent Malfunction ).
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Repair
the wiring harness.
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STEP 12. Check the wiring harness between A-46 PTC heater relay 1
connector terminal No.3 and D-213 engine-ECU connector terminal
No.41.
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note |
Prior to the wiring harness inspection, check
intermediate connector A-03, and repair
if necessary.
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- Check the PTC heater relay 1 earth line for open or short
circuit.
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Q.
Is the check result normal?
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Go to Step 13.
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Repair
the wiring harness.
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STEP 13. Check the wiring harness between A-46 PTC heater relay 1
connector terminal No.2 and D-128 PTC heater 1 connector terminal
No.2.
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- Check the PTC heater relay 1 power supply line for open
circuit.
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Q.
Is the check result normal?
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The
trouble can be an intermittent malfunction (Refer to GROUP 00, How to Cope
with Intermittent Malfunction ).
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Repair
the wiring harness.
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STEP 14. Check the wiring harness between D-08 A/C-ECU connector
terminal
No.14 and D-213 engine-ECU connector terminal No.35.
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- Check the engine-ECU input line for open circuit.
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Q.
Is the check result normal?
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Go to Step 15.
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Repair
the wiring harness.
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STEP 15. Replace the A/C-ECU and recheck the trouble
symptom
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Check that the front blower motor operates
normally.
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Q.
Is the check result normal?
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This
diagnosis is complete.
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Replace the engine-ECU.
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