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Last Modified: 11-27-2007 1.6 U
Service Category: Vehicle Interior Section: Heating/Air Conditioning
Model Year: 2008 Model: LX570 Doc ID: RM000002LIP008X
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: TERMINALS OF ECU (2008 LX570)

TERMINALS OF ECU

1. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY



(a) Disconnect the E36, E35 and z45 air conditioning amplifier connectors.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

E36-6 (+B1) - E36-1 (GND)

R - W-B

Battery power source

Always

11 to 14 V

E36-7 (+B2) - E36-1 (GND)

R - W-B

Battery power source

Always

11 to 14 V

z45-3 (B BUS) - z45-1 (BUS G)

-

Power supply for BUS IC (for front)

Always

11 to 14 V

z45-10 (B BUS) - z45-8 (BUS G)

-

Power supply for BUS IC (for front)

Always

11 to 14 V

E36-5 (IG+) - E36-1 (GND)

G - W-B

Ignition power supply

Engine switch on (IG)

11 to 14 V

Engine switch off

Below 1 V

E36-14 (RBBU) - E36-12 (RBUG)

L - BR

Power supply for BUS IC (for rear)

Always

11 to 14 V

E35-25 (TR3) - Body ground

V - Body ground

Ground
  • Engine switch on (IG)
  • Driver side duct sensor temperature: 25°C (77°F)

5000 +/-150 Ω

E35-26 (TR4) - Body ground

W - Body ground

Ground
  • Engine switch on (IG)
  • Passenger side duct sensor temperature: 25°C (77°F)

5000 +/-150 Ω

E35-16 (SG-2) - Body ground

G - Body ground

Ground for pressure sensor

Always

Below 1 Ω

E35-29 (SG-5) - Body ground

G - Body ground

Ground for compressor signal

Always

Below 1 Ω

E36-2 (E1) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

E36-1 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

E35-6 (E2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

E35-32 (SG-1) - Body ground

B - Body ground

Ground for room temperature sensor (for front)

Always

Below 1 Ω

z45-6 (SGA) - Body ground

-

Ground for evaporator temperature sensor

Always

Below 1 Ω

z45-1 (BUS G) - Body ground

-

Ground for BUS IC (for front)

Always

Below 1 Ω

z45-8 (BUS G) - Body ground

-

Ground for BUS IC (for front)

Always

Below 1 Ω

E35-34 (SGND) - Body ground

BR - Body ground

Ground for duct sensor (for driver side)

Always

Below 1 Ω

E35-12 (SG-9) - Body ground

L - Body ground

Ground for duct sensor (for passenger side)

Always

Below 1 Ω

E35-2 (SG-6) - Body ground

G - Body ground

Ground for room temperature sensor signal (for rear LH and rear RH)

Always

Below 1 Ω

E36-12 (RBUG) - Body ground

BR - Body ground

Ground for BUS IC (for rear)

Always

Below 1 Ω

E35-1 (SG) - Body ground

P - Body ground

Ground for evaporator temperature sensor signal (for rear)

Always

Below 1 Ω

If the result is not as specified, there may be a malfunction on the wire harness side.

(c) Reconnect the E36, E35 and z45 air conditioning amplifier connectors.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

E36-25 (CFN+) - Body ground

R - Body ground

Condenser FAN operation signal

Engine switch on (IG)

11 to 14 V

E36-33 (COOL) - Body ground

W - Body ground

Cool box operation signal

Engine switch on (IG)

Cool box switch on

Below 1 V

Engine switch on (IG)

Cool box switch off

11 to 14 V

E36-29 (AC1) - Body ground

L - Body ground

Compressor operation signal

Engine switch on (IG)

A/C switch off

11 to 14 V

Engine switch on (IG)

A/C switch on

Below 1 V

E36-22 (ACT) - Body ground

G - Body ground

Compressor operation signal

Engine switch on (IG)

ACT signal off

4.5 to 5.5 V

Engine switch on (IG)

ACT signal on

Below 1 V

E35-28 (LOCK) - E35-29 (SG-5)

L - G

Air compressor lock sensor signal

Engine idling

A/C switch on

Blower switch lo

Pulse generation

(see waveform 1)

E35-10 (TAM) - E35-16 (SG-2)

V - G

Ambient temperature sensor signal

Engine switch on (IG)

Ambient temperature:

25°C (77°F)

1.4 to 1.6 V

Engine switch on (IG)

Ambient temperature:

50°C (122°F)

0.7 to 0.9 V

E35-27 (S5-1) - E35-16 (SG-2)

LG - G

Power supply for pressure sensor

Engine switch on (IG)

4.5 to 5.5 V

E35-20 (PRE) - E35-16 (SG-2)

R - G

Air conditioning pressure sensor signal

Refrigerant pressure:

Normal pressure (less than 3.0732 MPa [31.4 kgf/cm2, 445 psi] and more than 0.1762 MPa [1.8 kgf/cm2, 25 psi])

1.0 to 4.8 V

Refrigerant pressure:

Abnormal (less than 0.1762 MPa [1.8 kgf/cm2, 25 psi])

Below 1 V

Refrigerant pressure:

Abnormal (more than 3.0732 MPa [31.4 kgf/cm2, 445 psi])

4.8 V or higher

E36-18 (MGC) - E36-1 (GND)

R - W-B

A/C compressor magnetic clutch operation signal

Engine idling

Blower switch lo

A/C switch on

Below 1 V

E36-3 (BLW) - E36-1 (GND)

R - W-B

Blower motor control signal

Engine switch on (IG)

Blower switch lo

Pulse generation

(see waveform 2)

E35-30 (SG-4) - E35-23 (DGS)

L - L

Exhaust gas sensor signal (CO, HC)

30 seconds after engine switch on (IG) and sensor exposed to exhaust gas

1.0 to 4.5 V

E35-30 (SG-4) - E35-24 (DGS1)

L - W

Exhaust gas sensor signal (NOx)

30 seconds after engine switch on (IG) and sensor exposed to exhaust gas

1.0 to 4.5 V

E35-9 (TR) - E35-32 (SG-1)

W - B

Room temperature sensor signal (for front)

Engine switch on (IG)

Front side interior temperature: 25°C (77°F)

1.9 to 2.1 V

Room temperature sensor signal (for front)

Engine switch on (IG)

Front side interior temperature: 50°C (122°F)

1.0 to 2.0 V

E35-7 (TSD) - Body ground

LG - Body ground

Driver side solar sensor signal

Engine switch on (IG)

Solar sensor subjected to electric light

0.8 to 4.3 V

E35-8 (TSP) - Body ground

GR - Body ground

Passenger side solar sensor signal

Engine switch on (IG)

Solar sensor subjected to electric light

0.8 to 4.3 V

z45-7 (TEA) - z45-6 (SGA)

-

Evaporator temperature sensor signal

Engine switch on (IG)

Evaporator temperature: 15°C (59°F)

1.0 to 1.2 V

z45-2 (BUS) - z45-1 (BUS G)

-

BUS IC control signal (for front)

Engine switch on (IG)

Pulse generation

z45-9 (BUS) - z45-8 (BUS G)

-

BUS IC control signal (for front)

Engine switch on (IG)

Pulse generation

E35-18 (TR) - E35-2 (SG-6)

R - G

Room temperature sensor signal (for rear LH)

Engine switch on (IG)

Vehicle interior temperature: 25°C (77°F)

1.9 to 2.1 V

Engine switch on (IG)

Vehicle interior temperature: 50°C (122°F)

1.0 to 1.2 V

E35-19 (TR7) - E35-2 (SG-6)

R - G

Room temperature sensor signal (for rear RH)

Engine switch on (IG)

Vehicle interior temperature: 25°C (77°F)

1.9 to 2.1 V

Engine switch on (IG)

Vehicle interior temperature: 50°C (122°F)

1.0 to 1.2 V

E36-13 (RBUS) - E36-12 (RBUG)

R - BR

BUS IC control signal (for rear)

Engine switch on (IG)

Pulse generation

E35-17 (TEC) - E35-1 (SG)

W - P

Evaporator temperature sensor signal (for rear)

Engine switch on (IG)

Evaporator temperature:

15°C (59°F)

1.4 to 1.8 V

E36-31 (ALT) - Body ground

R - Body ground

Generator signal

Engine idling

Pulse generation

E36-27 (PTC1) - Body ground

R - Body ground

PTC1 heater relay operation signal

Engine idling

Set temperature: Hi

Engine coolant temperature: Below 65°C (149°F)

Ambient temperature: Below 10°C (50°F)

Blower switch off → lo

Below 1 V → 11 to 14 V

E36-26 (PTC2) - Body ground

R - Body ground

PTC2 heater relay operation signal

E36-35 (PTC3) - Body ground

R - Body ground

PTC3 heater relay operation signal

E36-17 (BLWH) - E36-1 (GND)

L - W-B

Blower motor control signal (for rear)

Engine switch on (IG)

Blower switch lo

Pulse generation

(see waveform 3)

E36-19 (RMGV) - E36-1 (GND)

B - W-B

Rear cooling unit expansion valve signal

Engine switch on (IG)

11 to 14 V

If the result is not as specified, the air conditioning amplifier assembly may have a malfunction.


(e) Using an oscilloscope, check waveform 1.

A/C Compressor Lock Sensor Signal

Item

Content

Terminal No. (Symbol)

E35-28 (LOCK) - E35-29 (SG-5)

Tool Setting

200 mV/DIV., 10 ms/DIV.

Condition

Engine is running

Blower switch lo

A/C switch on

HINT:

When the rear blower level is increased, the duty ratio changes accordingly.

(f) Using an oscilloscope, check waveform 2.

Blower Motor Control Signal

Item

Content

Terminal No. (Symbol)

E36-3 (BLW) - E36-1 (GND)

Tool Setting

1 V/DIV., 500 μs/DIV.

Condition

Engine switch on (IG)

Blower switch lo

HINT:

When the blower level is increased, the duty ratio changes accordingly.

(g) Using an oscilloscope, check waveform 3.

Rear Blower Motor Control Signal

Item

Content

Terminal No. (Symbol)

E36-17 (BLWH) - E36-1 (GND)

Tool Setting

1 V/DIV., 500 μs/DIV.

Condition

Engine switch on (IG)

Blower switch lo

HINT:

When the rear blower level is increased, the duty ratio changes accordingly.

2. CHECK DISPLAY AND NAVIGATION MODULE DISPLAY*1, MULTI-DISPLAY*2

*1: w/ Navigation System

*2: w/o Navigation System



(a) Disconnect the F28 display connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

F28-1 (+B1) - F28-10 (GND1)

R - W-B

Battery

Always

11 to 14 V

F28-2 (ACC) - F28-10 (GND1)

GR - W-B

Accessory (ON)

Engine switch off

Below 1 V

F28-2 (ACC) - F28-10 (GND1)

GR - W-B

Accessory (ON)

Engine switch on (ACC)

11 to 14 V

F28-3 (IG) - F28-10 (GND1)

G - W-B

Ignition (ON)

Engine switch off

Below 1 V

F28-3 (IG) - F28-10 (GND1)

G - W-B

Ignition (ON)

Engine switch on (IG)

11 to 14 V

F28-10 (GND1) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

If the result is not as specified, there may be a malfunction on the wire harness side.

3. CHECK NO. 2 AIR CONDITIONING CONTROL ASSEMBLY



(a) Disconnect the E55 switch connector.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

E55-6 (IG) - E55-1 (E)

G - W-B

IG power supply

Always

11 to 14 V

E55-1 (E) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

If the result is not as specified, there may be a malfunction on the wire harness side.

4. CHECK MAIN BODY ECU (COWL SIDE JUNCTION BLOCK LH)



(a) Disconnect the 2A, 2B, 2D, E1, E2 and E3 ECU connectors.

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

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

2B-20 (BATB) - Body ground

L - Body ground

Battery power supply

Always

11 to 14 V

2D-62 (GND2) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

E3-1 (GND3) - Body ground

BR - Body ground

Ground

Always

Below 1 Ω

2A-1 (ACC) - 2D-62 (GND2)

B - W-B

ACC power supply

Engine switch off

Below 1 V

Engine switch on (ACC)

11 to 14 V

E1-6 (AM1) - 2D-62 (GND2)

W - W-B

Battery power supply

Always

11 to 14 V

E2-1 (AM2) - 2D-62 (GND2)

W - W-B

Battery power supply

Always

11 to 14 V

2A-1 (IG) - 2D-62 (GND2)

B - W-B

IG power supply

Engine switch off

Below 1 V

Engine switch on (IG)

11 to 14 V

If the result is not as specified, there may be a malfunction in the wire harness.