Toyota Tacoma 2015-2018 Service Manual: PTC Heater Circuit

Toyota Tacoma 2015-2018 Service Manual / Air Conditioning / Air Conditioning System(for Manual Air Conditioning System) / PTC Heater Circuit

DESCRIPTION

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

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses for circuits related to this system before performing the following inspection procedure.

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Enter the following menus: Body Electrical / Air Conditioner / Active Test.

(e) Check the operation by referring to the table below.

Air Conditioner

Tester Display	Test Part	Control Range	Diagnostic Note
Heater Active Level	Quick heater assembly	Min.: 0, Max.: 3	-

OK:

Heater Active Level changes normally.

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	INSPECT PTC HTR RELAY

(a) Remove the PTC HTR relays.

(b) Inspect the PTC HTR relays (See page ).

REPLACE PTC HTR RELAY

3.	CHECK HARNESS AND CONNECTOR (PTC HTR RELAY - POWER SOURCE CIRCUIT)

(a) Remove the PTC HTR relays.

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

Standard Voltage:

PTC HTR NO. 1

Tester Connection	Condition	Specified Condition
PTC HTR NO. 1-1 - Body ground	Always	11 to 14 V
PTC HTR NO. 1-5 - Body ground	Always	11 to 14 V

PTC HTR NO. 2

Tester Connection	Condition	Specified Condition
PTC HTR NO. 2-1 - Body ground	Always	11 to 14 V
PTC HTR NO. 2-5 - Body ground	Always	11 to 14 V

PTC HTR NO. 3

Tester Connection	Condition	Specified Condition
PTC HTR NO. 3-1 - Body ground	Always	11 to 14 V
PTC HTR NO. 3-5 - Body ground	Always	11 to 14 V

REPAIR OR REPLACE HARNESS OR CONNECTOR

4.	CHECK HARNESS AND CONNECTOR (PTC HTR RELAY - AIR CONDITIONING AMPLIFIER ASSEMBLY)

(a) Remove the PTC HTR relays.

(b) Disconnect the A14 air conditioning amplifier assembly connector.

Standard Resistance:

PTC HTR NO. 1

Tester Connection	Condition	Specified Condition
PTC HTR NO. 1-2 - A14-15 (PTC1)	Always	Below 1 Ω
PTC HTR NO. 1-2 or A14-15 (PTC1) - Body ground	Always	10 kΩ or higher

PTC HTR NO. 2

Tester Connection	Condition	Specified Condition
PTC HTR NO. 2-2 - A14-14 (PTC2)	Always	Below 1 Ω
PTC HTR NO. 2-2 or A14-14 (PTC2) - Body ground	Always	10 kΩ or higher

PTC HTR NO. 3

Tester Connection	Condition	Specified Condition
PTC HTR NO. 3-2 - A14-13 (PTC3)	Always	Below 1 Ω
PTC HTR NO. 3-2 or A14-13 (PTC3) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

5.	CHECK HARNESS AND CONNECTOR (QUICK HEATER ASSEMBLY - PTC HTR RELAY AND BODY GROUND)

(a) Remove the PTC HTR relays.

(b) Disconnect the Q1 quick heater assembly connector.

Standard Resistance:

PTC HTR NO. 1

Tester Connection	Condition	Specified Condition
PTC HTR NO. 1-3 - Q1-3 (B)	Always	Below 1 Ω
Q1-2 (E) - Body ground	Always	Below 1 Ω
Q1-4 (E) - Body ground	Always	Below 1 Ω
PTC HTR NO. 1-3 or Q1-3 (B) - Body ground	Always	10 kΩ or higher

PTC HTR NO. 2

Tester Connection	Condition	Specified Condition
PTC HTR NO. 2-3 - Q1-1 (B)	Always	Below 1 Ω
Q1-2 (E) - Body ground	Always	Below 1 Ω
PTC HTR NO. 2-3 or Q1-1 (B) - Body ground	Always	10 kΩ or higher

PTC HTR NO. 3

Tester Connection	Condition	Specified Condition
PTC HTR NO. 3-3 - Q1-5 (B)	Always	Below 1 Ω
Q1-4 (E) - Body ground	Always	Below 1 Ω
PTC HTR NO. 3-3 or Q1-5 (B) - Body ground	Always	10 kΩ or higher

REPAIR OR REPLACE HARNESS OR CONNECTOR

6.	INSPECT QUICK HEATER ASSEMBLY

(a) Remove the quick heater assembly (See page (b) Inspect the quick heater assembly (See page ).

(b) Inspect the quick heater assembly (See page ).

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPLACE QUICK HEATER ASSEMBLY

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