Toyota Sequoia (2005). Manual - part 89

–

DIAGNOSTICS

ENGINE

DI–159

353

6

Check whether DTC output recurs (DTC P0138, P0158)

CHECK:
(a)

On the hand–held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC
INFO / CURRENT CODES.

(b)

Read DTCs.

RESULT:

Display (DTC Output)

Proceed To

P0138 or P0158

A

No output

B

B

Check for intermittent problems 
(See page 

DI–11

).

A

Replace heated oxygen sensor.

7

Check output voltage of heated oxygen sensor.

PREPARATION:
(a)

Connect the hand–held tester to the DLC3.

(b)

Turn the ignition switch to ON and turn the tester ON.

(c)

Start the engine.

(d)

Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST / ALL / O2S B1S2.

(e)

After warming up the engine, run the engine at an engine speed of 2,500 rpm for 3 minutes.

CHECK:
(a)

Read the output voltage of the HO2 sensor when the engine rpm is suddenly increased.

HINT:
Quickly accelerate the engine to 4,000 rpm 3 times using the accelerator pedal.

Standard: Fluctuates between 0.4 V or less and 0.5 V or more.

NG

Go to step 14.

OK

8

Perform confirmation driving pattern.

NEXT

DI–160

–

DIAGNOSTICS

ENGINE

354

9

Check whether DTC output recurs (DTC P0136, P0156)

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

P0136 or P0156

A

No output

B

B

Check for intermittent problems 
(See page 

DI–11

).

A

10

Replace heated oxygen sensor.

NEXT

11

Perform confirmation driving pattern.

NEXT

12

Check whether DTC output recurs (DTC P0136, P0156)

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

P0136 or P0156

A

No output

B

B

Repair completed.

A

B17391

+12 %

Normal

Malfunction

–12 %

0 V

3.3 V

1 V

A/F Sensor Output

HO2 Sensor Output

Injection Volume

Malfunction

–

DIAGNOSTICS

ENGINE

DI–161

355

13

Perform active test (injection volume).

PREPARATION:
(a)

Connect the hand–held tester to the DLC3.

(b)

Start the engine and turn the tester ON.

(c)

Warm up the engine.

(d)

Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / INJ VOL.

CHECK:
(a)

Change the fuel injection volume using the tester, monitoring the voltage output of Air–Fuel Ratio (A/F)
and HO2 sensors displayed on the tester.

HINT:

Change the fuel injection volume within the range of –12 % and +12 %. The injection volume can be
changed in 1 % graduations within the range.

The A/F sensor is displayed as AFS B1S1 (AFS B2S1), and the HO2 sensor is displayed as O2S B1S2
(O2S B2S2), on hand–held testers.

RESULT:

Tester Display (Sensor)

Voltage Variations

Proceed To

AFS B1S1 (AFS B2S1) (A/F)

Alternates between more and less than 3.3 V

OK

AFS B1S1 (AFS B2S1) (A/F)

Remains at more than 3.3 V

NG

AFS B1S1 (AFS B2S1) (A/F)

Remains at less than 3.3 V

NG

HINT:
A normal HO2 sensor voltage (O2S B1S2 (O2S B2S2)) reacts in accordance with increases and decreases
in fuel injection volumes. When the A/F sensor voltage remains at either less or more than 3.3 V despite the
HO2 sensor indicating a normal reaction, the A/F sensor is malfunctioning.

NG

Replace air–fuel ratio (A/F) sensor.

OK

A21341

+B

OX

E1

HT

H2

H4

Components Side:

Bank 1 Sensor 2, Bank 2 Sensor 2

DI–162

–

DIAGNOSTICS

ENGINE

356

check and repair extremely rich or lean actu-
arial air fuel ratio (injector, fuel pressure, gas
leakages from exhaust system, etc.)

14

Check for exhaust gas leakage.

CHECK:
Check for exhaust gas leakage from the exhaust manifold and pipe.
OK: No exhaust gas leakage.

NG

Repair or replace exhaust gas leakage point.

OK

15

Inspect heated oxygen sensor.

PREPARATION:
Disconnect the HO2 sensor connector.
CHECK:
Measure the resistance between the terminals of the HO2 sen-
sor connector.
OK:

Standard:

Tester Connections

Specified Conditions

HT (2) – +B (1)

11 to 16 

Ω

 at 20



C (68



F)

HT (2) – E (3)

10 k

Ω

 or higher

NG

Replace heated oxygen sensor.

OK