Toyota CH-R Service Manual: PTC Heater Circuit

Toyota CH-R Service Manual / Heating / Air Conditioning / Air Conditioning System(for Automatic Air Conditioning System With Top-mounted Air Conditioner Pressure Sensor) / PTC Heater Circuit

DESCRIPTION

The air conditioning amplifier assembly sends operation signals to the PTC heater relays when quick heater assembly operation conditions are met. Based on the signals from the air conditioning amplifier assembly, the PTC heater relays turn on, and power is supplied to the quick heater assembly installed in the air conditioning radiator assembly.

Quick Heater Assembly Operation Condition

Control ECU

Condition

Air Conditioning Amplifier Assembly

Ignition switch ON

ECO mode: off

Blower switch: On

Temperature setting: MAX HOT

Light control switch off
  • Engine coolant temperature 65°C (149°F) or lower (3 PTC heater relays operating)
  • Engine coolant temperature 70°C (158°F) or lower (2 PTC heater relays operating)
  • Engine coolant temperature 75°C (167°F) or lower (1 PTC heater relay operating)
  • Ambient temperature -7°C (19°F) or lower (3 PTC heater relays operating)
  • Ambient temperature 16°C (61°F) or lower (2 PTC heater relays operating)
  • Ambient temperature 25°C (77°F) or lower (1 PTC heater relay operating)

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM (HEATER ACTIVE LEVEL)

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch ON.

(c) Turn the Techstream on.

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

(e) Perform the Active Test according to the display on the Techstream.

Body Electrical > Air Conditioner > Active Test

Tester Display

Measurement Item

Control Range

Diagnostic Note

Heater Active Level

Quick heater assembly

Min.: 0

Max.: 3

-
Body Electrical > Air Conditioner > Active Test

Tester Display

Heater Active Level

OK:

Heater Active Level changes normally.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT PTC HEATER RELAY

(a) Remove the PTC heater relays.

(b) Inspect the PTC heater relays.

Click here

NG

REPLACE PTC HEATER RELAY
OK

3.

CHECK HARNESS AND CONNECTOR (PTC HEATER RELAY - POWER SOURCE)

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

Standard Voltage:

PTC HTR NO. 1

Tester Connection

Switch Condition

Specified Condition

Relay terminal 3 - Body ground

Always

11 to 14 V

Relay terminal 1 - Body ground

Ignition switch off

Below 1 V

Relay terminal 1 - Body ground

Ignition switch ON

11 to 14 V

Standard Voltage:

PTC HTR NO. 2

Tester Connection

Switch Condition

Specified Condition

Relay terminal 3 - Body ground

Always

11 to 14 V

Relay terminal 1 - Body ground

Ignition switch off

Below 1 V

Relay terminal 1 - Body ground

Ignition switch ON

11 to 14 V

Standard Voltage:

PTC HTR NO. 3

Tester Connection

Switch Condition

Specified Condition

Relay terminal 3 - Body ground

Always

11 to 14 V

Relay terminal 1 - Body ground

Ignition switch off

Below 1 V

Relay terminal 1 - Body ground

Ignition switch ON

11 to 14 V

*1

NO. 1 ENGINE ROOM RELAY BLOCK

*2

PTC HTR NO. 1 Relay

*3

PTC HTR NO. 2 Relay

*4

PTC HTR NO. 3 Relay
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

4.

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

(a) Disconnect the F72 air conditioning amplifier assembly connectors.

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

Standard Resistance:

PTC HTR NO. 1

Tester Connection

Condition

Specified Condition

Relay terminal 2 - F72-19 (PTC1)

Always

Below 1 Ω

Relay terminal 2 or F72-19 (PTC1) - Body ground

Always

10 kΩ or higher

Standard Resistance:

PTC HTR NO. 2

Tester Connection

Condition

Specified Condition

Relay terminal 2 - F72-39 (PTC2)

Always

Below 1 Ω

Relay terminal 2 or F72-39 (PTC2) - Body ground

Always

10 kΩ or higher

Standard Resistance:

PTC HTR NO. 3

Tester Connection

Condition

Specified Condition

Relay terminal 2 -F72-20 (PTC3)

Always

Below 1 Ω

Relay terminal 2 or F72-20 (PTC3) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

5.

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

(a) Disconnect the H2 quick heater assembly connectors.

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

Standard Resistance:

PTC HTR NO. 1

Tester Connection

Condition

Specified Condition

Relay terminal 5 - H2-3 (B)

Always

Below 1 Ω

H2-2 (E) - Body ground

Always

Below 1 Ω

H2-4 (E) - Body ground

Always

Below 1 Ω

Relay terminal 5 or H2-3 (B) - Body ground

Always

10 kΩ or higher

Standard Resistance:

PTC HTR NO. 2

Tester Connection

Condition

Specified Condition

Relay terminal 5 - H2-1 (B)

Always

Below 1 Ω

H2-2 (E) - Body ground

Always

Below 1 Ω

Relay terminal 5 or H2-1 (B) - Body ground

Always

10 kΩ or higher

Standard Resistance:

PTC HTR NO. 3

Tester Connection

Condition

Specified Condition

Relay terminal 5 - H2-5 (B)

Always

Below 1 Ω

H2-4 (E) - Body ground

Always

Below 1 Ω

Relay terminal 5 or H2-5 (B) - Body ground

Always

10 kΩ or higher
NG

REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

6.

INSPECT QUICK HEATER ASSEMBLY

(a) Remove the quick heater assembly.

Click here

(b) Inspect the quick heater assembly.

Click here

OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPLACE QUICK HEATER ASSEMBLY

    Blower Motor Circuit
    DESCRIPTION The blower motor with fan sub-assembly is operated by signals from the air conditioning amplifier assembly through the blower resistor. Blower motor speed signals are transmitted in a ...

    Ambient Temperature Display System
    DESCRIPTION The outside temperature sensor is installed in front of the cooler condenser assembly to detect the ambient temperature which is used to control the air conditioning system AUTO mode. ...

    Other materials:

    Toyota CH-R Service Manual > Can Communication System: Data List / Active Test
    DATA LIST / ACTIVE TEST NOTICE: In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on these reference values when deciding whether a part is faulty or not. HINT: Using the Techstream to read the Data List allows the values or s ...

    Toyota CH-R Service Manual > Vehicle Stability Control System: ABS Operates Before Necessary When Braking
    DESCRIPTION Troubleshooting for when ABS operates too soon due to a noisy signal from the speed sensor, a difference in output, etc. PROCEDURE 1. PERFORM TEST MODE (SIGNAL CHECK) INSPECTION (SPEED SENSOR CIRCUIT) (a) Using the Techstream, perform a Test Mode (Si ...

    Toyota C-HR (AX20) 2023-2026 Owner's Manual

    Toyota CH-R Owners Manual

    Toyota CH-R Service Manual

    © 2017-2026 Copyright www.tochr.net
    0.0086