HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM: TERMINALS OF ECU (2008 Sequoia)

TERMINALS OF ECU

1. CHECK AIR CONDITIONING AMPLIFIER

(a) Disconnect the H24, H67 and z13 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
H24-1 (IG+) - Body ground	P - Body ground	Ignition power supply	Ignition switch ON	11 to 14 V
H24-1 (IG+) - Body ground	P - Body ground	Ignition power supply	Ignition switch off	Below 1 V
H24-14 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
H24-21 (B) - Body ground	R - Body ground	Battery power source	Always	11 to 14 V
H67-20 (RGND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
H67-24 (+B2) - Body ground	LG - Body ground	Battery power source	Always	11 to 14 V

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

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

HINT:

Check from the rear of the connector with it connected to the air conditioning amplifier.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
H24-5 (TAM) - H24-13 (SG-2)	V - G	A/C ambient temperature sensor signal	Ignition switch ON at 25°C (77°F)	1.35 to 1.75 V
H24-5 (TAM) - H24-13 (SG-2)	V - G	A/C ambient temperature sensor signal	Ignition switch ON at 40°C (104°F)	0.9 to 1.2 V
H24-8 (LOCK) - H24-13 (SG-2)	SB - G	A/C compressor lock sensor signal	Engine is running Blower switch LO A/C switch ON	Pulse generation (see waveform 1)
H24-9 (PRE) - Body ground	Y - Body ground	A/C pressure sensor signal	Refrigerant pressure: normal	0.5 to 4.8355 V
H24-10 (S5-3) - Body ground	R - Body ground	Power supply for presser sensor	Ignition switch ON	4.5 to 5.5 V
H24-11 (CANH) - H24-14 (GND)	B - W-B	Hi-level CAN bus line	Ignition switch ON	Pulse generation (see waveform 2)
H24-12 (CANL) - H24-14 (GND)	W - W-B	Lo-level CAN bus line	Ignition switch ON	Pulse generation (see waveform 3)
H24-13 (SG-2) - Body ground	G - Body ground	Ground for ambient temperature sensor	Always	Below 1 Ω
H24-17 (AC1) - H24-14 (GND)	B - W-B	Idle-up request signal	Engine idling Magnet Clutch is not engaged	11 to 14 V
H24-17 (AC1) - H24-14 (GND)	B - W-B	Idle-up request signal	Engine idling Magnet Clutch is engaged	Below 1 V
H24-18 (MHTR) - H24-14 (GND)	L - W-B	Mirror heater relay drive signal	Mirror heater switch OFF→ON	11 to 14 V → Below 1 V
H24-20 (MGC) - H24-14 (GND)	P - W-B	A/C compressor magnetic clutch operation signal	Ignition switch ON Blower switch LO A/C switch OFF	11 to 14 V
H24-20 (MGC) - H24-14 (GND)	P - W-B	A/C compressor magnetic clutch operation signal	Ignition switch ON Blower switch LO A/C switch ON	Below 1 V
H24-23 (BLW) - H24-14 (GND)	LG - W-B	Blower motor control signal	Ignition switch ON Blower switch LO	Pulse generation (see waveform 4)
H24-27 (ACT) - H24-14 (GND)	L - W-B	A/C compressor magnetic clutch on permit signal	Engine idling → Accelerator pedal depressed (Air conditioning cut signal output when engine load increases rapidly)	11 to 14 V → Below 2 V
H24-29 (TR) - H24-34 (SG-1)	G - B	Room temperature sensor signal	Ignition switch ON Front side interior temperature: 25°C (77°F)	1.8 to 2.2 V
H24-32 (TSP) - Body ground	L - Body ground	Passenger side solar sensor signal	Ignition switch ON Solar sensor subjected to electric light	0.8 to 4.3 V
H24-33 (TSD) - Body ground	P - Body ground	Driver side solar sensor signal	Ignition switch ON Solar sensor subjected to electric light	0.8 to 4.3 V
H24-34 (SG-1) - Body ground	B - Body ground	Ground for room temperature sensor	Always	Below 1 Ω
H24-37 (LIN1) - H24-14 (GND)	SB - W-B	LIN communication signal	Ignition switch ON	Pulse generation
H24-38 (RDEF) - H24-14 (GND)	R - W-B	Defogger relay drive signal	Defogger switch OFF→ON	11 to 14 V → Below 1 V
H24-39 (CFN+) - H24-14 (GND)	V - W-B	Condenser fan relay drive signal	Ignition switch ON Condenser fan OFF→ON	11 to 14 V → Below 1 V
H24-40 (D) - H24-14 (GND)	GR - W-B	Deicer relay drive signal	Deicer switch OFF→ON	11 to 14 V → Below 1 V
H67-1 (RBUS) - H67-21 (RBUG)	V - G	BUS IC control signal	Ignition switch off → ON	Pulse generation
H67-4 (TEC) - H67-19 (SGND)	R - L	Rear evaporator temperature sensor signal	Ignition switch ON Evaporator temperature at 0°C (32°F)	1.7 to 2.1 V
H67-6 (SG-5) - Body ground	BR - Body ground	Ground for seat blower switch	Always	Below 1 Ω
H67-7 (SG-6) - Body ground	P - Body ground	Ground for rear room temperature sensor	Always	Below 1 Ω
H67-8 (S5-2) - H67-6 (SG-5)	SB - BR	Power supply for seat blower switch	Ignition switch ON	4.5 to 5.5 V
H67-9 (SHD+) - H67-20 (RGND)	W - W-B	Driver seat blower drive signal	Ignition switch ON	Pulse generation
H67-10 (SHP+) - H67-20 (RGND)	O - W-B	Passenger seat blower drive signal	Ignition switch ON	Pulse generation
H67-13 (RLIN) - H67-20 (RGND)	B - W-B	LIN communication signal	Ignition switch ON	Pulse generation
H67-15 (AD-4) - H67-20 (RGND)	GR - W-B	Driver seat blower switch signal	Ignition switch ON Driver seat blower switch 0 position	4.5 to 5.5 V
H67-15 (AD-4) - H67-20 (RGND)	GR - W-B	Driver seat blower switch signal	Ignition switch ON Driver seat blower switch 3 position	Below 1 V
H67-16 (AD-5) - H67-20 (RGND)	W - W-B	Passenger seat blower switch signal	Ignition switch ON Passenger seat blower switch 0 position	4.5 to 5.5 V
H67-16 (AD-5) - H67-20 (RGND)	W - W-B	Passenger seat blower switch signal	Ignition switch ON Passenger seat blower switch 3 position	Below 1 V
H67-17 (TR) - H67-7 (SG-6)	L - P	Rear room temperature sensor signal	Ignition switch ON Rear side interior temperature: 25°C (77°F)	1.8 to 2.2 V
H67-19 (SGND) - Body ground	L - Body ground	Ground for rear evaporator temperature sensor	Always	Below 1 Ω
H67-21 (RBUG) - Body ground	G - Body ground	Ground for BUS IC	Always	Below 1 Ω
H67-22 (BLWH) - H67-20 (RGND)	P - W-B	Blower motor control signal	Ignition switch ON Blower switch LO	Pulse generation (see waveform 5)
H67-23 (RBBU) - H67-21 (RBUG)	Y - G	Power supply for BUS IC	Ignition switch off	Below 1 V
H67-23 (RBBU) - H67-21 (RBUG)	Y - G	Power supply for BUS IC	Ignition switch ON	11 to 14 V
z13-2 (BUS G) - Body ground	-	Ground for BUS IC	Always	Below 1 Ω
z13-3 (BUS) - z13-2 (BUS G)	-	BUS IC control signal	Ignition switch off → ON	Pulse generation
z13-4 (B BUS) - z13-2 (BUS G)	-	Power supply for BUS IC	Ignition switch off	Below 1 V
z13-4 (B BUS) - z13-2 (BUS G)	-	Power supply for BUS IC	Ignition switch ON	11 to 14 V
z13-5 (SGA) - Body ground	-	Ground for evaporator temperature sensor	Always	Below 1 Ω
z13-6 (TEA) - z13-5 (SGA)	-	A/C evaporator temperature sensor signal	Ignition switch ON Evaporator temperature at 0°C (32°F)	1.7 to 2.1 V
z13-6 (TEA) - z13-5 (SGA)	-	A/C evaporator temperature sensor signal	Ignition switch ON Evaporator temperature at 15°C (59°F)	0.7 to 1.3 V

If the result is not as specified, the ECU may have a malfunction.

(e) Waveform 1: Using an oscilloscope

Compressor Lock Signal

Terminal Name

LOCK - SG-2

Tester Range

200 mV/DIV., 10 ms./DIV.

Condition

Engine is running

Blower switch LO

A/C switch ON

(f) Waveform 2 (Reference) : Using an oscilloscope

CAN Communication Signal

Terminal Name	CANH - GND
Tester Range	1 V/DIV., 10 μsec./DIV.
Condition	Ignition switch ON

HINT:

The waveform varies depending on the CAN communication signal.

(g) Waveform 3 (Reference) : Using an oscilloscope

CAN Communication Signal

Terminal Name	CANL - GND
Tester Range	1 V/DIV., 10 μsec./DIV.
Condition	Ignition switch ON

HINT:

The waveform varies depending on the CAN communication signal.

(h) Waveform 4 : Using an oscilloscope

Blower Motor Control Signal

Terminal Name

BLW - GND

Tester Range

1 V/DIV., 500 μsec./DIV.

Condition

Ignition switch ON

Blower switch LO

HINT:

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

(i) Waveform 5 : Using an oscilloscope

Blower Motor Control Signal

Terminal Name

BLWH - RGND

Tester Range

1 V/DIV., 500 μsec./DIV.

Condition

Ignition switch ON

Blower switch LO

HINT:

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

(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
H45-16 (IG+) - H45-1 (GND)	P - W-B	Ignition power supply	Ignition switch ON	11 to 14 V
Ignition switch off	Below 1 V
H45-1 (GND) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω
H45-9 (OFF) - H45-10 (AUTO)	GR - LG	Steering pad switch signal	Always	10 kΩ or higher
Steering pad switch push to AUTO	Below 2.5 Ω
Steering pad switch push to OFF	313 to 345 Ω
Steering pad switch push to TEMP+	950 to 1050 Ω
Steering pad switch push to TEMP-	2955 to 3266 Ω

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

H45-16 (IG+) - H45-1 (GND)

P - W-B

Ignition power supply

Ignition switch ON

11 to 14 V

Ignition switch off

Below 1 V

H45-1 (GND) - Body ground

W-B - Body ground

Ground

Always

Below 1 Ω

H45-9 (OFF) - H45-10 (AUTO)

GR - LG

Steering pad switch signal

Always

10 kΩ or higher

Steering pad switch push to AUTO

Below 2.5 Ω

Steering pad switch push to OFF

313 to 345 Ω

Steering pad switch push to TEMP+

950 to 1050 Ω

Steering pad switch push to TEMP-

2955 to 3266 Ω

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

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
H45-3 (STX) - H45-1 (GND)	SB - W-B	LIN communication signal	Ignition switch ON	Pulse generation

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

H45-3 (STX) - H45-1 (GND)

SB - W-B

LIN communication signal

Ignition switch ON

Pulse generation

If the result is not as specified, the integration control and panel may have a malfunction.

(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
S4-1 (IG) - S4-4 (E)	P - W-B	Ignition power supply	Ignition switch ON	11 to 14 V
Ignition switch off	Below 1 V
S4-4 (E) - Body ground	W-B - Body ground	Ground	Always	Below 1 Ω

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

S4-1 (IG) - S4-4 (E)

P - W-B

Ignition power supply

Ignition switch ON

11 to 14 V

Ignition switch off

Below 1 V

S4-4 (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.

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
S4-5 (RLIN) - S4-4 (E)	GR - W-B	LIN communication signal	Ignition switch ON	Pulse generation

Terminal No. (Symbol)

Wiring Color

Terminal Description

Condition

Specified Condition

S4-5 (RLIN) - S4-4 (E)

GR - W-B

LIN communication signal

Ignition switch ON

Pulse generation

If the result is not as specified, the air conditioning control panel may have a malfunction.