Toyota Sequoia (2005). Manual - part 56

DICEL–02

–

DIAGNOSTICS

ENGINE

DI–27

221

READINESS MONITOR DRIVE PATTERN

1.

PURPOSE OF THE READINESS TESTS

The On–Board Diagnostic (OBD II) system is designed to monitor the performance of emission–re-
lated components and report any detected abnormalities in the form of Diagnostic Trouble Codes
(DTCs). Since the various components need to be monitored during different driving conditions, the
OBD II system is designed to run separate monitoring programs called Readiness Monitors. Many
state Inspection and Maintenance (I/M) programs require that vehicles complete their Readiness Mon-
itors prior to beginning an emission test.

The current status of the Readiness Monitors can be seen by using the hand–held tester with version
9.0 software (or newer), or a generic OBD II Scan tool.

To view the Readiness Monitor status using the hand–held tester, select ”Monitor Status” from the En-
hanced OBD II Menu.

A status of ”complete” indicates that the necessary conditions have been met to run the performance
tests for the related Readiness Monitor.

The Readiness Monitor will be reset to ”incomplete” if:

ECM has lost power (battery or fuse).

DTCs have been cleared.

The conditions for running the Readiness Monitor have not been met.

In the event that any Readiness Monitor shows ”incomplete,” follow the appropriate Readiness Monitor
Drive Pattern to activate the monitor and change the readiness status to ”complete.”

CAUTION:
Strictly observe the posted speed limits, traffic laws, and road conditions when performing these
drive patterns.
NOTICE:
These drive patterns represent the fastest method to satisfy all necessary conditions which allow
the specific readiness monitor to complete.
In the event that the drive pattern must be interrupted (possibly due to traffic conditions or other fac-
tors) the drive pattern can be resumed, and in most cases, the readiness monitor will still set to ”com-
plete”.
To ensure rapid completion of readiness monitors, avoid sudden changes in vehicle load and speed
(driving up and down hills and/or sudden acceleration).

Contents:

TITLE

STEP(s)

CATALYST MONITOR

2

EVAP MONITOR

3, 4

AIR–FUEL RATIO (A/F) AND OXYGEN SENSOR (O2S) MONITOR

5

OXYGEN SENOSR HEATER MONITOR

6

A23510

Vehicle Speed

(64 km/h and 113 km/h)

Between 
40 mph and 70 mph

Idling

Ignition Switch OFF

10 minutes

Time

Warm up

(Note: Even when vehicle stops during driving pattern, test can be resumed)

NOTICE: 
This test will not be completed 
if the vehicle is driven under 
absolute constant speed 
condition such as with cruise 
control activated.

(6)

(5)

DI–28

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DIAGNOSTICS

ENGINE

222

2.

CATALYST MONITOR (ACTIVE AIR–FUEL RATIO CONTROL TYPE)

(a)

Preconditions
The monitor will not run unless:

The MIL is OFF

(b)

Drive Pattern
(1)

Connect a hand–held tester or OBD II scan tool to the DLC3.

(2)

Turn the ignition switch to ON.

(3)

Turn the tester or scan tool ON.

(4)

Clear DTCs (where set) (see page 

DI–43

).

(5)

Start the engine and warm it up.

(6)

Drive the vehicle at between 40 mph and 70 mph (64 km/h and 113 km/h) for at least 10 minutes.

(c)

Monitor Status
(1)

Check the Readiness Monitor status displayed on the tester or scan tool.

(2)

If the status does not switch to COMPL (complete), extend the driving time.

A18910

Idling

Ignition OFF

Warmed up

Soak

15 to 50 min.

(When the readiness code or diagnostic code
is set, this test is completed.)

3,000 rpm

10 sec.

–

DIAGNOSTICS

ENGINE

DI–29

223

3.

EVAP MONITOR (VACUUM PRESSURE MONITOR)

NOTICE:
A cold soak must be performed prior to conducting the drive pattern to complete the Internal Pres-
sure Readiness Monitor.
(a)

Cold Soak Preconditions
The monitor will not run unless:

MIL is OFF

Fuel level is approximately 1/2 to 3/4

Altitude is 7,800 feet (2,400 m) or less

(b)

Cold Soak Procedure
Let the vehicle cold soak for 8 hours or until the difference between IAT and ECT becomes less than
7

°

C (13

°

F)

HINT:
Examples:

Scenario 1
ECT = 24

°

C (75

°

F)

IAT = 16

°

C (60

°

F)

Difference between ECT and IAT is 8

°

C (15

°

F)

→

 The monitor will not run because difference between ECT and IAT is greater than 7

°

C (13

°

F)

Scenario 2
ECT = 21

°

C (70

°

F)

IAT = 20

°

C (68

°

F)

Difference between ECT and IAT is 1

°

C (2

°

F)

→

 The monitor will run because difference between ECT and IAT is less than 7

°

C (13

°

F)

4.

EVAP MONITOR (VACUUM PRESSURE MONITOR) (CONTINUED)

DI–30

–

DIAGNOSTICS

ENGINE

224

(a)

Preconditions
The monitor will not run unless:

MIL is OFF

Fuel level is approximately 1/2 to 3/4

Altitude is 7,800 feet (2,400 m) or less

Engine Coolant Temperature (ECT) is between 4.4

°

C and 35

°

C (40

°

F and 95

°

F)

Intake Air Temperature (IAT) is between 4.4

°

C and 35

°

C (40

°

F and 95

°

F)

Cold Soak Procedure has been completed

Before starting the engine, the difference between ECT and IAT must be less than 7

°

C (13

°

F)

HINT:
Examples:

Scenario 1
ECT = 24

°

C (75

°

F)

IAT = 16

°

C (60

°

F)

Difference between ECT and IAT is 8

°

C (15

°

F)

→

 The monitor will not run because difference between ECT and IAT is higher than 7

°

C (13

°

F)

Scenario 2
ECT = 21

°

C (70

°

F)

IAT = 20

°

C (68

°

F)

Difference between ECT and IAT is 1

°

C (2

°

F)

→

 The monitor will run because difference between ECT and IAT is less than 7

°

C (13

°

F)

The readiness test can be completed in cold ambient conditions (less than 40

°

F / 4.4

°

C) and/or at

high altitudes (more than 7,800 feet / 2,400 m) if the drive pattern is repeated a second time after cycl-
ing the ignition off.
(b)

Drive Pattern
(1)

Connect the OBD II scan tool to DLC3 to check monitor status and preconditions (refer to (a)).

(2)

Release pressure in fuel tank by removing the fuel tank cap and then reinstall it.

(3)

Start the engine and allow it to idle until ECT becomes 75

°

C (167

°

F) or higher.

(4)

Run the engine at 3,000 rpm for approximately 10 seconds.

(5)

Allow the engine to idle with the A/C ON (to create slight load) for 15 to 50 minutes.

NOTICE:
If the vehicle is not equipped with A/C, put a slight load on the engine by doing the following :

Securely set the parking brake.

Block the drive wheels with wheel chocks.

Allow the vehicle to idle in drive for 15 to 50 minutes.