2001 TOYOTA SEQUOIA engine

I18
Ignition
SW
A23552
ECM
STOPSTP
ALT
BatteryE4
16 G±Y
J/C1 S14 Stop Light SW
2
G±W
BR7
Stop
Light
LH
R8
Stop
Light
RH3
5
8W±R
A W
High
Mounted
Stop Light
W±B 1L
1 1F
7
F10
Fusible
Link
BlockInstrument
Panel J/B1
4EG±Y
4B8
Brake Inhibit Relay
G±Y 4
See VSC System 2
W
J19
J/CB
C
IC
CC
C
4
BD1
1
22
1H9 H9(*1)
(*2) (*1)(*2)
BD2
12 J/C
A1
4
G±W IG2
*1: w/o Rear Spoiler
*2: w/ Rear Spoiler AM2
To Towing
Converter Relay
W±BST1±
E4 15
4C 4A1
1
3
L±B Sub J/B No.4
2
IGN1 B±O2
4D2
4A
1E 17
2 1C
1 A
J44J11
J/C J10
J
J33
J34 C
3
IJ
52C
2D 11
AM2
B W±RB±R
6
Instrument
Panel J/B
BP1
4 G±W B±O
G±W
G±W G±WSub J/B No.4
J10
J45
4
BJ J57
J/CA
W±BW±B G±W
High
Mounted
Stop LightG±WJ20
J/C G±W H
Engine Room
J/B DI±284
± DIAGNOSTICSENGINE
478 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM

± DIAGNOSTICSENGINE
DI±285
479 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions when
a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was
running or stopped, if the engine was warmed up or not, if the air±fuel ratio was lean or rich, as well as other
data from the time when a malfunction occurred.
1 Check operation of stop light.
CHECK:
Check if the stop lights come on and go off normally when the brake pedal is operated and released.
NG Check and repair stop light circuit.
OK
2 Check stop light switch (See page BE±47).
NG Replace stop light switch.
OK

B17446
Brake Pedal
DepressedBrake Pedal
Released ON
() ()
ST1±(+)E4
E6
E1(±)
DI±286
± DIAGNOSTICSENGINE
480 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check STP signal and ST1± voltage.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON.
(c) Select the item ºDIAGNOSIS / ENHANCED OBD II /
DATA LIST / ALL / STOP LIGHT SWº.
CHECK:
Read the signal displayed on the hand±held tester.
OK:
Standard:
Brake PedalSpecified Condition
DepressedSTP Signal ON
ReleasedSTP Signal OFF
CHECK:
Measure the voltage between the specified terminals of the E4
and E6 ECM connectors.
OK:
Standard:
Tester ConnectionBrake PedalSpecified Condition
ST1± (E4±12) ±
E1 (E6±1)DepressedBelow 1.5 V
ST1± (E4±12) ±
E1 (E6±1)Released7.5 to 14 V
OK Check for intermittent problems (See page
DI±11).
NG

B17447
Wire Harness Side:
Stop Light Switch Connector
S14
ST1±STP
E4
± DIAGNOSTICSENGINE
DI±287
481 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check harness and connector between ECM and stop light switch.
PREPARATION:
(a) Disconnect the S14 stop light switch connector.
(b) Disconnect the E4 ECM connector.
CHECK:
Measure the resistance between the wire harness side connec-
tors.
OK:
Standard:
Tester ConnectionSpecified Condition
Stop light switch (S14±1) ± STP (E4±15)Below 1 W
Stop light switch (S14±3) ± ST1±
(E4±16)Below 1 W
Stop light switch (S14±1) or
STP (E4±15) ± Body ground10 kW or higher
Stop light switch (S14±3) or
ST1± (E4±16) ± Body ground10 kW or higher
NG Repair or replace harness or connector.
OK
Replace ECM (See page SF±80).

A20823
Idle engine
RPM
Small Target RPM
Actual idle RPMLarge
Learned value
of the idle speed
controlMaximum
Minimum
Time 0
Time DI±288
± DIAGNOSTICSENGINE
482 Author: Date:
2005 SEQUOIA (RM1146U)
DTC P0505 Idle Air Control System
CIRCUIT DESCRIPTION
The idle speed is controlled by the ETCS (Electronic Throttle Control System).
The ETCS is composed of the throttle motor which operates the throttle valve, and the throttle position sen-
sor, which detects the opening angle of the throttle valve.
The ECM controls the throttle motor to provide the proper throttle valve opening angle to obtain the target
idle speed.
DTC No.DTC Detection ConditionTrouble Area
P0501Idle speed continues to vary greatly from target speed
(2 trip detection logic)

ETCS

Air induction system

PCV hose connection

ECM
MONITOR DESCRIPTION
The ECM regulates the idle speed by opening and closing the throttle valve using the ETCS. The ECM con-
cludes that the idle speed control ECM function is malfunctioning if: 1) the actual idle RPM varies more than
the specified amount, or 2) a learning value of the idle speed control remains at the maximum or minimum
five times or more during a driving cycle. The ECM will turn on the MIL and set a DTC.
Example:
If the actual idle RPM varies from the target idle RPM by more than 100 (*1) rpm five times during a driving
cycle, the ECM will turn on the MIL and a DTC is set.
HINT:
*1: RPM threshold varies with engine load.
DICF6±02

± DIAGNOSTICSENGINE
DI±289
483 Author: Date:
2005 SEQUOIA (RM1146U)
MONITOR STRATEGY
Related DTCsP0505Idle air control malfunction
Main sensors/componentsCrankshaft position sensor
Required sensors/componentsRelated sensors/componentsVehicle speed sensor, Engine coolant tempera-
ture sensor
Frequency of operationOnce per driving cycle
Duration10 min.
MIL operation2 driving cycles
Sequence of operationNone
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever this DTC is
not presentSee page DI±18
EngineRunning
TYPICAL MALFUNCTION THRESHOLDS
Detection CriteriaThreshold
Either of the following conditions is met:Condition 1 or 2
1. Frequency that both of the following conditions (a) and (b)
are met:5 times or more
(a) Engine RPM ± target engine RPMLess than ±100 rpm or more than 150 rpm
(b) Vehicle conditionStop after vehicle was driven by 10 km/h (6.25 mph) or more
2. Frequency that both of the following conditions (a) and (b)
are met:Once
(a) Engine RPM ± target engine RPMLess than ±100 rpm or more than 150 rpm
(b) Intake air control flow rate learning value2.48 L/sec. or less, or 11 L/sec. or more

DI±290
± DIAGNOSTICSENGINE
484 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:

When the throttle position is slightly opened (the accelerator pedal is slightly depressed) because a
floor carpet is overlapped on the accelerator pedal, or if the accelerator pedal is not fully released, etc.,
DTC P0505 will possibly be detected.

Read freeze frame data using the hand-held tester. Freeze frame data records the engine conditions
when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the
vehicle was running or stopped, if the engine was warmed up or not, if the air±fuel ratio was lean or
rich, as well as other data from the time when a malfunction occurred.
1 Are there any other codes (besides P0505) being output?
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON and push the hand±held tester main switch ON.
(c) When using hand±held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / CURRENT CODES.
CHECK:
Read the DTC using the hand±held tester.
RESULT:
Display (DTC Output)Proceed to
P0505A
ºP0505º and other DTCsB
HINT:
If any other codes besides P0505 are output, perform the troubleshooting for those DTCs first.
B Go to relevant DTC chart (See page DI±58).
A
2 Check connection of PCV piping.
NG Repair or replace PCV piping.
OK

± DIAGNOSTICSENGINE
DI±291
485 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check air induction system (See page SF±1).
CHECK:
Check for vacuum leaks in air induction system.
OK:

No leakage.
NG Repair or replace air induction system.
OK
Check electric throttle control system
(See page SF±39).