2001 TOYOTA SEQUOIA engine

I28845
ECM
E5
E5G±BIntegration Control
and Panel
I22
ACT
AC1
8 25
24
L±W 2
21
5 MG CLT Relay
J3 J/C
15
IG4 C
C Engine Room J/B
2
2C4
2G
3
A3
A/C Magnetic Clutch
and Lock Sensor R±Y
IA1 LG±B5
4
Engine Room R/B No. 2
2 22 G±Y
MGC 5
I19 I22 ACT
AC1
IA5
R±Y1
L±W L±W
R±Y
L
L
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2381
2575 Author: Date:
2005 SEQUOIA (RM1146U)
Compressor Circuit
CIRCUIT DESCRIPTION
The integration control and panel outputs the magnetic clutch ON signal from terminal AC1 to the ECM.
When the ECM receives this signal, it sends a signal from terminal ACT and switches the A/C magnetic clutch
relay ON. This turns the A/C magnetic clutch on.
WIRING DIAGRAM
DIAA8±03

DI±2382
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2576 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Read value of hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main SW ON.
CHECK:
Select the item below in the DATA LIST, and read the displays on the hand±held tester.
ENGINE AND ECT / ALL:
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic Note
A/C SIGA/C signal / ON or OFF
A/C SW Pushed: ON

A/C SW Released: OFF±
HINT:
Check with the engine running.
OK:
The display is as specified in the normal condition.
NG Go to step 8.
OK
2 Read value of hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main SW ON.
CHECK:
Select the item below in the DATA LIST, and read the displays on the hand±held tester.
ENGINE AND ECT / ALL:
ItemMeasurement Item / Display
(Range)Normal ConditionDiagnostic Note
A/C MAG CLUTCHA/C magnet clutch / ON or OFF
A/C SW ON: ON

A/C SW OFF: OFF±
HINT:
Check with the engine running.
OK:
The display is as specified in the normal condition.
NG Replace ECM (See page SF±80).
OK

± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2383
2577 Author: Date:
2005 SEQUOIA (RM1146U)
3 Perform active test by hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main SW ON.
CHECK:
Select the item below in the DATA LIST, and read the displays on the hand±held tester.
AIR CONDITIONING:
ItemTest Details / Display (Range)Diagnostic Note
A/C MAG CLUTCHMagnet clutch relay / OFF, ONOperating sound can be heard
HINT:
Check with the engine running.
OK:
The operation sound of the MG CLT relay can be heard.
NG Go to step 5.
OK
4 Check harness and connector between integration control and panel (ACT termi-
nal) and ECM (ACT terminal) (See page IN±35).
NG Repair or replace harness or connector.
OK
Proceed to next circuit inspection shown in problem symptoms table (See page DI±2304).

Z18060
15 2
3
12 3 5
I21361
3
DI±2384
± DIAGNOSTICSAIR CONDITIONING SYSTEM
2578 Author: Date:
2005 SEQUOIA (RM1146U)
5 Check magnetic clutch relay.
PREPARATION:
Remove the magnetic clutch relay from the engine room J/B.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:
Tester connectionConditionSpecified condition
3 ± 5Always10 kW or higher
3 ± 5
Voltage is applied
between terminals
1 and 2Below 1W (Battery
voltage is applied between
terminals 1 and 2)
NG Replace magnetic clutch relay.
OK
6 Check A/C magnetic clutch.
PREPARATION:
Disconnect the magnetic clutch connector.
CHECK:
Connect the positive (+) battery lead to the magnetic clutch con-
nector terminal 3.
OK:
Magnetic clutch is energized.
NG Replace A/C magnetic clutch.
OK
7 Check harness and connector between integration control and panel (MGC ter-
minal) and body ground (See page IN±35).
NG Repair or replace harness or connector.
OK
Replace integration control and panel.

I28847
AC1 Integration Control and Panel
I22
± DIAGNOSTICSAIR CONDITIONING SYSTEM
DI±2385
2579 Author: Date:
2005 SEQUOIA (RM1146U)
8 Check harness and connector between integration control and panel (AC1 termi-
nal) and ECM (AC1 terminal) (See page IN±35).
NG Repair or replace harness or connector.
OK
9 Check voltage between terminal AC1 of integration control and panel connector
and body ground.
PREPARATION:
(a) Disconnect the connector from the ECM.
(b) Remove the integration control and panel with the con-
nectors still connected.
(c) Start the engine and push the AUTO switch.
CHECK:
Measure the voltage between terminal AC1 of the integration
control and panel connector and body ground when the mag-
netic clutch is turned ON and OFF by the A/C switch.
OK:
Switch operationTester connectionSpecified condition
ONAC1 ± Body ground1.3 to 2.6 V
OFFAC1 ± Body ground3.7 to 4.5 V
NG Replace integration control and panel.
OK
Replace ECM (See page SF±80).

EM0KQ±08
B13343
CO/HC Meter
± ENGINE MECHANICALCO/HC
EM±1
2580 Author: Date:
2005 SEQUOIA (RM1146U)
CO/HC
INSPECTION
HINT:
This check is used only to determine whether or not the idle CO/
HC complies with regulations.
1. INITIAL CONDITIONS
(a) Engine at normal operating temperature
(b) Air cleaner installed
(c) All pipes and hoses of air induction system connected
(d) All accessories switched OFF
(e) All vacuum lines properly connected
(f) SFI system wiring connectors fully plugged
(g) Ignition timing checked correctly
(h) Transmission in neutral position
(i) Tachometer and CO/HC meter calibrated by hand
2. START ENGINE
3. RACE ENGINE AT 2,500 RPM FOR APPROX. 180
SECONDS
4. INSERT CO/HC METER TESTING PROBE AT LEAST
40 cm (1.3 ft) INTO TAILPIPE DURING IDLING

EM±2
± ENGINE MECHANICALCO/HC
2581 Author: Date:
2005 SEQUOIA (RM1146U)
5. IMMEDIATELY CHECK CO/HC CONCENTRATION AT
IDLE AND/OR 2,500 RPM
HINT:
When performing the 2 mode (2,500 rpm and idle) test, follow
the measurement orders are prescribed by the applicable local
regulations.
If the CO/HC concentration does not comply with regulations,
perform troubleshooting in the order given below.
(a) Check the air±fuel ratio sensors and heated oxygen sen-
sors operation.(See page DI±88 and DI±93)
(b) See the table below for possible causes, and then inspect
and correct the applicable causes if necessary.
COHCProblemsCauses
NormalHighRough idle7. Faulty ignitions:

Incorrect timing

Fouled, shorted or improperly gapped plugs
8. Incorrect valve clearance
9. Leaky intake and exhaust valves
10.Leaky cylinders
LowHighRough idle
(fluctuating HC reading)1. Vacuum leaks:

PCV hoses

Intake manifold

Throttle body

Brake booster line
2. Lean mixture causing misfire
HighHighRough idle
(Black smoke from exhaust)1. Restricted air filter
2. Faulty SFI systems:

Faulty pressure regulator

Defective ECT sensor

Faulty ECM

Faulty injectors

Faulty throttle position sensor

Faulty MAF meter

EM0KR±10
A04458
Compression
Gauge
± ENGINE MECHANICALCOMPRESSION
EM±3
2582 Author: Date:
2005 SEQUOIA (RM1146U)
COMPRESSION
INSPECTION
HINT:
If there is lack of power, excessive oil consumption or poor fuel
economy, measure the compression pressure.
1. WARM UP AND STOP ENGINE
Allow the engine to warm up to normal operating temperature.
2. REMOVE SPARK PLUGS (See page IG±1)
3. CHECK CYLINDER COMPRESSION PRESSURE
(a) Insert a compression gauge into the spark plug hole.
(b) Fully open the throttle.
(c) While cranking the engine, measure the compression
pressure.
HINT:
Always use a fully charged battery to obtain engine speed of
250 rpm or more.
(d) Repeat steps (a) through (c) for each cylinder.
NOTICE:
This measurement must be done in as short a time as pos-
sible.
Compression pressure:
1,373 kPa (14.0 kgf/cm
2, 199 psi) or more
Minimum pressure:
1,030 kPa (10.5 kgf/cm
2, 149 psi)
Difference between each cylinder:
98 kPa (1.0 kgf/cm
2, 14 psi) or less
(e) If the cylinder compression in one or more cylinders is low,
pour small amount of engine oil into the cylinder through
the spark plug hole and repeat steps (a) through (c) for
cylinders with low compression.

If adding oil helps the compression, chances are
that the piston rings and/or cylinder bore are worn
or damaged.

If pressure stays low, a valve may be sticking or
seating is improper, or there may be leakage past
the gasket.
4. REINSTALL SPARK PLUGS (See page IG±1)