AIR CONDITIONING SYSTEM (for Manual Air Conditioning System) > PTC Heater Circuit

for Preparation Click here


DESCRIPTION

PTC heater relays are closed in accordance with signals from the air conditioning amplifier assembly and power is supplied to the PTC heater assembly installed on the radiator heater unit.

WIRING DIAGRAM


E177083E03


INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedures.

1.INSPECT PTC HEATER RELAY (PTC NO. 1, PTC NO. 2, PTC NO. 3)
E140239E03

  1. Remove the PTC heater relays from the No. 2 engine room relay block.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    3 - 5
    		Voltage is not applied between terminals 1 and 2
    		10 kΩ or higher
    3 - 5
    		Apply the battery voltage between terminals 1 and 2
    		Below 1 Ω

  1. Reinstall the PTC heater relays.

Text in Illustration 
*1
No. 1 PTC Heater Relay (PTC NO. 1)*3
*2
No. 1 PTC Heater Relay (PTC NO. 1)*4
No. 2 and No. 3 Heater Relay (PTC NO. 2, PTC NO. 3)
*3: for 1ND-TV
*4: for 1KR-FE


NG
REPLACE PTC HEATER RELAY
OK


2.CHECK HARNESS AND CONNECTOR (FUSE - PTC HEATER RELAY)
E176915E06

  1. Remove the PTC heater relays from the No. 2 engine room relay block.

  1. Measure the voltage according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    PTC NO. 1-5 - Body ground
    		Always
    		11 to 14 V
    PTC NO. 2-5 - Body ground
    		Always
    		11 to 14 V
    PTC NO. 3-5 - Body ground
    		Always
    		11 to 14 V

  1. Reinstall the PTC heater relays.

Text in Illustration 
*1
Component without relay installed
(No. 2 Engine Room Relay Block)
*2
PTC NO. 1 Relay
*3
PTC NO. 2 Relay
*4
PTC NO. 3 Relay
*5
for 1KR-FE
*6
for 1ND-TV


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3.CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - BODY GROUND)


    E176915E06

  1. Remove the PTC heater relays from the No. 2 engine room relay block.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    PTC NO. 1-1 - Body ground
    		Always
    		Below 1 Ω
    PTC NO. 2-1 - Body ground
    		Always
    		Below 1 Ω
    PTC NO. 3-1 - Body ground
    		Always
    		Below 1 Ω

  1. Reinstall the PTC heater relays.

Text in Illustration 
*1
Component without relay installed
(No. 2 Engine Room Relay Block)
*2
PTC NO. 1 Relay
*3
PTC NO. 2 Relay
*4
PTC NO. 3 Relay
*5
for 1KR-FE
*6
for 1ND-TV


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


4.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (HEATER ACTIVE LEVEL)


    E176915E06

  1. Remove the PTC heater relays from the No. 2 engine room relay block.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Body / Air Conditioner / Active Test / Heater Active Level.

  1. Measure the voltage when changing the control range with the intelligent tester, according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    PTC NO. 1-2 - Body ground
    		Heater Active Level 0
    		Below 1 V
    Heater Active Level 1
    		11 to 14 V
    Heater Active Level 2
    		11 to 14 V
    Heater Active Level 3
    		11 to 14 V
    PTC NO. 2-2 - Body ground
    		Heater Active Level 0
    		Below 1 V
    Heater Active Level 1
    		Below 1 V
    Heater Active Level 2
    		11 to 14 V
    Heater Active Level 3
    		11 to 14 V
    PTC NO. 3-2 - Body ground
    		Heater Active Level 0
    		Below 1 V
    Heater Active Level 1
    		Below 1 V
    Heater Active Level 2
    		Below 1 V
    Heater Active Level 3
    		11 to 14 V

  1. Reinstall the PTC heater relays.

Text in Illustration 
*1
Component without relay installed
(No. 2 Engine Room Relay Block)
*2
PTC NO. 1 Relay
*3
PTC NO. 2 Relay
*4
PTC NO. 3 Relay
*5
for 1KR-FE
*6
for 1ND-TV


NG
Go to step 7
OK


5.INSPECT PTC HEATER ASSEMBLY


    E177085E01

  1. Disconnect the A44 PTC heater assembly connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - Ground terminal
    		Always
    		Below 1 Ω
    2 - Ground terminal
    		Always
    		Below 1 Ω
    3 - Ground terminal
    		Always
    		Below 1 Ω

  1. Reconnect the PTC heater assembly connector.

Text in Illustration 
*1
Component without harness connected
(PTC Heater Assembly)
*2
Component without harness connected
(Ground Terminal (for PTC Heater Assembly))


NG
REPLACE PTC HEATER ASSEMBLY (Click here)
OK


6.PERFORM ACTIVE TEST USING INTELLIGENT TESTER (HEATER ACTIVE LEVEL)


    E152214E04

  1. Disconnect the A44 PTC heater assembly connector.

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

  1. Enter the following menus: Body / Air Conditioner / Active Test / Heater Active Level.

  1. Measure the voltage when changing the control range with an intelligent tester, according to the value(s) in the table below.

    Standard Voltage:
    Tester Connection
    		Condition
    		Specified Condition
    A44-1 (B) - Body ground
    		Heater Active Level 0
    		Below 1 V
    Heater Active Level 1
    		Below 1 V
    Heater Active Level 2
    		Below 1 V
    Heater Active Level 3
    		11 to 14V
    A44-2 (B) - Body ground
    		Heater Active Level 0
    		Below 1 V
    Heater Active Level 1
    		11 to 14V
    Heater Active Level 2
    		11 to 14V
    Heater Active Level 3
    		11 to 14V
    A44-3 (B) - Body ground
    		Heater Active Level 0
    		Below 1 V
    Heater Active Level 1
    		Below 1 V
    Heater Active Level 2
    		11 to 14V
    Heater Active Level 3
    		11 to 14V

  1. Reconnect the PTC heater assembly connector.

Text in Illustration 
*1
Front view of wire harness connector
(to PTC Heater Assembly)


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR (PTC HEATER RELAY - PTC HEATER ASSEMBLY)
OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (Click here)  

7.CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - AIR CONDITIONING AMPLIFIER)


    E177090E01

  1. Remove the PTC heater relays from the No. 2 engine room relay block.

  1. Disconnect the D17 air conditioning amplifier connector.

  1. Measure the resistance according to the value(s) in the table below.

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    PTC NO. 1-2 - D17-9 (PTC1)
    		Always
    		Below 1 Ω
    PTC NO. 2-2 - D17-10 (PTC2)
    		Always
    		Below 1 Ω
    PTC NO. 3-2 - D17-12 (PTC3)
    		Always
    		Below 1 Ω

  1. Reinstall the PTC heater relays.

  1. Reconnect the air conditioning amplifier connector.

Text in Illustration 
*1
Component without relay installed
(No. 2 Engine Room Relay Block)
*2
Front view of wire harness connector
(to Air Conditioning Amplifier)
*3
PTC NO. 1 Relay
*4
PTC NO. 2 Relay
*5
PTC NO. 3 Relay
*6
for 1KR-FE
*7
for 1ND-TV


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER (Click here)