Toyota Sequoia (2005). Manual - part 97

–

DIAGNOSTICS

ENGINE

DI–191

385

HINT:
In order to memorize the DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in
the DATA LIST for the following period of time. Take care not to turn the ignition switch OFF. Turning the
ignition switch OFF switches the diagnosis system from check mode to normal mode, and all DTCs, etc.,
are erased.

Engine Speed

Time

Idling

3 minutes 30 seconds or more

1,000 rpm

3 minutes or more

2,000 rpm

1 minute 30 seconds or more

3,000 rpm

1 minute or more

(f)

Check if there is misfire, and the DTC and the freeze frame data. Record the DTC’s, freeze frame data
and misfire counter data.

(g)

Turn the ignition switch OFF and wait for at least 5 seconds.

INSPECTION PROCEDURE

HINT:

If DTCs besides misfire DTCs are memorized simultaneously, troubleshoot the non–misfire DTCs first.

If the misfire does not occur when the vehicle is brought to the workshop, the misfire can be confirmed
by reproducing the condition of the freeze frame data. Also, after finishing the repair, confirm that there
is no misfire (See confirmation driving pattern).

On 6 or 8 cylinder engines, misfiring cylinder identification is disabled at high engine speed and only
a general misfire fault code P0300 is stored instead of a cylinder specific misfire fault code (P0301 to
P0308).
If the misfire starts in a high engine speed area or the misfire occurs only in a high engine speed area,
only code P0300 may be stored.

When only a general misfire fault code like P0300 is stored:

Erase the general misfire fault code using the hand–held tester

Start the engine and drive the confirmation patten.

Read the value of the misfire ratio for each cylinder. Or read the DTC.

Repair the cylinder that has a high misfire ratio. Or repair the cylinder indicated by the DTC.

After finishing repairs, drive the confirmation pattern again and confirm that no misfire occurs.

When either of SHORT FT #1, LONG FT #1, SHORT FT #2 or LONG FT #2 in the freeze frame data
is over the range of 

±

20 %, there is a possibility that the air–fuel ratio is becoming RICH (–20 % or

less) or LEAN (+20 % or more).

When COOLANT TEMP in the freeze frame data is less than 80

°

C (176

°

F), there is a possibility of

misfire only during engine warm–up.

If the misfire cannot be reproduced, the following reasons may apply: 1) the vehicle has low fuel, 2)
improper fuel is being used, or 3) the ignition plug is contaminated.

Be sure to check the value on the misfire counter after the repair.

DI–192

–

DIAGNOSTICS

ENGINE

386

1

Are there any other codes (besides DTC P0300, P0301, P0302, P0303, P0304
P0305, P0306, P0307 or P0308) 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 DTCs using hand–held tester.
RESULT:

Display (DTC Output)

Proceed to

”P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 and/or

P0308”

A

”P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or

P0308” and other DTCs

B

HINT:
If any other codes besides ”P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307 or P0308” are
output, perform the troubleshooting for those DTCs.

B

Go to relevant DTC chart (See page 

DI–58

).

A

2

Check wire harness, connector and vacuum hose in engine room.

CHECK:
(a)

Check the connection conditions of the wire harness and connector.

(b)

Check for the disconnection, piping and brake of the vacuum hose.

NG

Repair or replace, then confirm that there is no
misfire (See confirmation driving pattern).

OK

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DIAGNOSTICS

ENGINE

DI–193

387

3

Check connection of PCV piping.

OK:

PCV hose is connected correctly and is not damaged.

NG

Repair or replace PCV piping.

OK

4

Connect hand–held tester, and read the number of misfire.

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)

Start the engine.

(d)

When using hand–held tester, enter the following menu: DIAGNOSIS / ENHANCED OBD II / DATA
LIST / ALL / CYL#1 to CYL#8.

CHECK:
Read the number of misfire on the hand–held tester.
HINT:
When a misfire is not reproduced, be sure to branch below based on the stored DTC.
RESULT:

High Misfire Rate Cylinder

Proceed to

1 or 2 cylinders

A

More than 3 cylinders

B

B

Go to step 15.

A

A19885

0.8 mm
(0.031 in.)

DI–194

–

DIAGNOSTICS

ENGINE

388

5

Check spark plug and spark of misfiring cylinder.

PREPARATION:
(a)

Remove the ignition coil assembly.

(b)

Remove the spark plug.

CHECK:
(a)

Check the electrode for carbon deposits.

(b)

Check the spark plug type (See page 

IG–1

).

(c)

Check electrode gap.

OK:

No large carbon deposit present.
Not wet with gasoline or oil.
Electrode gap: 0.8 mm (0.031 in.)

NOTICE:
If adjusting the gap of a new spark plug, bend only ”the
base / ground” electrode. Do not touch the tip. Never at-
tempt to adjust the gap of a used plug.
PREPARATION:
(a)

Install the spark plug to the ignition coil assembly.

(b)

Disconnect the injector connector.

(c)

Ground spark plug.

CHECK:
Check if spark occurs while engine is being cracked.
CAUTION:
Always disconnect each injector connector.
NOTICE:
Do not crank the engine for more than 2 seconds.
OK:

Spark occurs across electrode gap.

OK

Go to step 8.

NG