2001 TOYOTA SEQUOIA ECU

± DIAGNOSTICSENGINE
DI±395
589 Author: Date:
2005 SEQUOIA (RM1146U)

The ECM must establish a closed throttle valve position learning value to perform fuel cut. If the battery
terminal has been reconnected, the vehicle must be driven over 10 mph (16 km/h) to allow the ECM
to learn the closed throttle valve position.

When the vehicle is driven:
The output voltage of the A/F sensor may be below 0.56 V during fuel enrichment. For the vehicle, this
translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to over-
take another vehicle. The A/F sensor is functioning normally.

The A/F sensor is a current output element; therefore, the current is converted into a voltage inside
the ECM. Measuring the voltage at the connectors of the A/F sensor or ECM will show a constant volt-
age result.
NG Go to step 9.
OK
4 Perform confirmation driving pattern.
NEXT
5 Check whether DTC output recurs (DTC P2195, P2196, P2197 or P2198)
CHECK:
(a) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / PENDING CODES.
(b) Read DTCs.
RESULT:
Display (DTC Output)Proceed To
P2195, P2196, P2197 or P2198A
No outputB
B Go to step 5.
A

DI±396
± DIAGNOSTICSENGINE
590 Author: Date:
2005 SEQUOIA (RM1146U)
6 Replace air fuel ratio sensor.
NEXT
7 Perform confirmation driving pattern.
NEXT
8 Check whether DTC output recurs (DTC P2195, P2196, P2197 or P2198)
CHECK:
(a) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / PENDING CODES.
(b) Read DTCs.
RESULT:
Display (DTC Output)Proceed To
P2195, P2196, P2197 or P2198A
No outputB
B Go to step 5.
A
9 Confirm whether vehicle has run out of fuel in past.
NO Check for intermittent problems
(See page DI±11).
YES
DTC caused by running out of fuel.

DI±400
± DIAGNOSTICSENGINE
594 Author: Date:
2005 SEQUOIA (RM1146U)
16 Replace air fuel ratio sensor.
NEXT
17 Perform confirmation driving pattern.
NEXT
18 Check whether DTC output recurs (DTC P2195, P2196, P2197 or P2198)
CHECK:
(a) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / PENDING CODES.
(b) Read DTCs.
RESULT:
Display (DTC Output)Proceed To
P2195, P2196, P2197 or P2198A
No outputB
B Replace ECM (See page SF±80) and perform
confirmation driving pattern.
A
19 Confirm whether vehicle has run out of fuel in past.
NO Check for intermittent problems
(See page DI±11).
YES
DTC caused by running out of fuel.

± DIAGNOSTICSENGINE
DI±401
595 Author: Date:
2005 SEQUOIA (RM1146U)
20 Replace air fuel ratio sensor.
NEXT
21 Perform confirmation driving pattern.
NEXT
22 Check whether DTC output recurs (DTC P2195, P2196, P2197 or P2198)
CHECK:
(a) On the hand±held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / PENDING CODES.
(b) Read DTCs.
RESULT:
Display (DTC Output)Proceed To
P2195, P2196, P2197 or P2198 (A/F sensor pending DTCs)A
No outputB
B Replace ECM (See page SF±80).
A
END

DI±414
± DIAGNOSTICSENGINE
608 Author: Date:
2005 SEQUOIA (RM1146U)
TYPICAL ENABLING CONDITIONS
ItSpecificationItemMinimumMaximum
The monitor will run whenever these
DTCs are not presentSee page DI±18
Following values are when atmospheric is
760 mmHg (100 kPa)±
EVAP key±off monitor runs when all of the
following conditions met:±
Atmospheric pressure525 to 825 mmHg (70 to 110 kPa)
Battery voltage10.5 V±
Vehicle speed±4 km/h (2.5 mph)
Ignition switchOFF
Engine conditionNot running
Time after engine stopped5 hours
FTP sensor malfunction (P0450, P0452,
P0453)Not detected
Purge VSVNot operated by scan tool
Vent valveNot operated by scan tool
Leak detection pumpNot operated by scan tool
Both of the following conditions are met
before IG switch OFFCondition 1 and 2
1. Duration that vehicle is driven5 min.±
2. Purge flowExecuted
ECT4.4 to 35°C (40 to 95°F)
IAT4.4 to 35°C (40 to 95°F)
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Key±off monitor sequence1 to 8
1. Atmospheric pressure±
Next sequence is run if following condition
set±
Atmospheric pressure change for 10 sec.±2.25 mmHg (0.3 kPa) for 1 sec.
2. First reference pressure±
Next sequence is run if all of following
conditions setCondition 1, 2 and 3
1. FTP when 4 sec. after reference pres-
sure measurement±±7.5 mmHg (±1 kPa)
2. Reference pressure±36.38 to ±7.93 mmHg (±4.85 to ±1.057 kPa)
3. Reference pressureSaturated
3. Vent valve stuck closed check±
Next sequence is run if following condition
set±
FTP change for 10 sec. after vent valve
ON (closed)2.25 mmHg (0.3 kPa)±

DI±420
± DIAGNOSTICSENGINE
614 Author: Date:
2005 SEQUOIA (RM1146U) FTP sensor malfunction (P0450, P0452,
P0453)
Not detected
Purge VSVNot operated by scan tool
Vent valveNot operated by scan tool
Leak detection pumpNot operated by scan tool
Both of the following conditions are met
before IG switch OFFCondition 1 and 2
1. Duration that vehicle is driven5 min.±
2. Purge flowExecuted
ECT4.4 to 35°C (40 to 95°F)
IAT4.4 to 35°C (40 to 95°F)
Example of re±start time±
First time7 hours
Second time9 hours and 30 min.
Key±off monitor sequence1 to 8
1. Atmospheric pressure±
Next sequence is run if following condition
set±
Atmospheric pressure change for 10 sec.±2.25 mmHg (0.3 kPa) for 1 sec.
2. First reference pressure±
Next sequence is run if all of following
conditions setCondition 1, 2 and 3
1. FTP when 4 sec. after reference pres-
sure measurement±±7.5 mmHg (±1 kPa)
2. Reference pressure±36.38 to ±7.93 mmHg (±4.85 to ±1.057 kPa)
3. Reference pressureSaturated
3. Vent valve stuck closed check±
Next sequence is run if following condition
set±
FTP change for 10 sec. after vent valve
ON (closed)2.25 mmHg (0.3 kPa)±
4. Vacuum introduction and leak±
Next sequence is run if both of following
conditions setCondition 1 and 2
1. Vacuum introduction time±15 min.
2. FTPFTP was saturated
5. Purge VSV stuck closed check±
Next sequence is run if following condition
set±
FTP change for 10 sec. after purge VSV
ON (open)2.25 mmHg (0.3 kPa)±
6. Second reference pressure measure-
ment±
Next sequence is run if all of following
conditions setCondition 1, 2, 3 and 4
1. FTP when 4 sec. after reference pres-
sure measurement±±7.5 mmHg (±1 kPa)
2. Reference pressure±36.38 to ±7.93 mmHg (±4.85 to ±1.057 kPa)

B17435Vacuum Hose
DI±432
± DIAGNOSTICSENGINE
626 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check whether DTC output recurs.
PREPARATION:
(a) Start the engine and warm it up.
(b) Turn the ignition switch OFF.
(c) Connect a hand±held tester to the DLC3.
(d) Turn the ignition switch to ON and turn the tester ON.
(e) Clear the DTCs (see page DI±43).
(f) Start the engine.
CHECK:
(a) Perform SYSTEM CHECK to operate the air injection system.
Select the following menu items: DIAGNOSIS/ENHANCED OBD II/SYSTEM CHECK/AIR INJ
CHECK/AUTOMATIC OPERATION
(b) After operating the secondary air injection system, confirm the pending codes for the secondary air
injection system by selecting the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO
/ PENDING CODES.
(c) Read DTCs and check that no DTC is set.
OK:
DTC P2444 or P2445 for the secondary air injection system is not output.
NG Go to step 4.
OK
Check for intermittent problems
(See page DI±11).
4 Check vacuum hose.
CHECK:
(a) Remove the intake manifold (see page EM±36).
(b) Check the vacuum hose connection between the pres-
sure sensor and air switching valve.
OK:
The vacuum hose is securely connected.
CHECK:
(a) Check the vacuum hose for blockage or damage.
OK:
The vacuum hose has no blockage or damage.
NG Repair or replace vacuum hose.
OK

B17434
Pressure GaugePressure Sensor
B17436
± DIAGNOSTICSENGINE
DI±433
627 Author: Date:
2005 SEQUOIA (RM1146U)
5 Inspect ECM (air voltage).
PREPARATION:
(a) Remove the intake manifold (see page EM±36).
(b) Connect the pressure gauge to the pressure sensor as
shown in the illustration.
(c) Connect the hand±held tester to the DLC3 on the vehicle.
(d) Turn the ignition switch ON and push the hand±held tes-
ter main switch ON (Do not start engine).
(e) Select the following items: DIAGNOSIS / ENHANCED
OBD II / DATA LIST / AIR PUMP PRS.
CHECK:
Check that the pressure displayed on the hand±held tester fluc-
tuates when applying the pressure to the pressure sensor with
the pressure gauge.
OK:
Pressure fluctuates in response to the pressure ap-
plied with the pressure gauge.
NG Replace pressure sensor.
OK
6 Check connection of all air injection system piping and hoses.
CHECK:
(a) Remove the intake manifold (see page EM±36).
(b) Check that all the pipes and hoses between the air pump
and air switching valve are securely connected.
OK:
All the air injection pipes and hoses are securely con-
nected.
CHECK:
(a) Check the pipe and hoses for blockage or damage.
OK:
The air injection system pipes and hoses have no
blockage and damage.
NG Repair or replace air injection system piping.
OK