Toyota Sequoia (2005). Manual - part 150

–

DIAGNOSTICS

ENGINE

DI–395

589

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 P2198

A

No output

B

B

Go to step 5.

A

DI–396

–

DIAGNOSTICS

ENGINE

590

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 P2198

A

No output

B

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.

B17396

HT

+B

AF–

AF+

Sensor 1

A/F Sensor

Component Side:

Front View

A19288

A/F Relay

–

DIAGNOSTICS

ENGINE

DI–397

591

10

Check resistance of air–fuel ratio (A/F) sensor heater.

PREPARATION:
Disconnect the air–fuel ratio (A/F) sensor connector.
CHECK:
Measure resistance between the terminals of the A/F sensor
connector.
OK:

Tester Connection

Specified Condition

HT (1) – +B (2)

Between 1.8 

Ω

 and 3.4 

Ω

 at 20



C (68



F)

HT (1) – AF– (4)

10 k

Ω

 or higher

NG

Replace air–fuel ratio (A/F) sensor.

OK

11

Check A/F relay.

PREPARATION:
Remove the A/F relay from the engine room J/B.
CHECK:
Inspect the A/F relay.
OK:

Standard:

Terminal No.

Condition

Specified Condition

3 – 5

Always

10 K

Ω

 or higher

3 – 5

Apply B+ between 

terminals 1 and 2

Below 1  

Ω

NG

Replace EFI relay.

OK

A23659

Wire Harness Side:

HT

A38

Sensor 1

A/F Sensor Connector

AF+

Front View

AF–

+B

A39

B17415

A55007

E7 ECM Connector

HA1A

A1A+

A1A–

A2A+

A2A–

HA2A

A23512

Reference (Bank 1 Sensor 1 System Drawing):

A/F Sensor

A/F Relay

Heater

Sensor

A1A+

HA1A

Duty 
Control

ECM

From 
Battery

A/F Heater 
Fuse

A1A–

To EFI Relay

DI–398

–

DIAGNOSTICS

ENGINE

592

12

Check for open and short in harness and connector between ECM and A/F sen-
sor.

PREPARATION:
(a)

Disconnect the A38 or A39 A/F sensor connector.

(b)

Turn the ignition switch to ON.

CHECK:
(a)

Measure the voltage between the +B terminal of the A/F
sensor connector and body ground.
Standard:

Tester Connections

Specified Conditions

+B (2) – Body ground

Between 9 V and 14 V

PREPARATION:
(a)

Turn the ignition switch to OFF.

(b)

Disconnect the E7 ECM connector.

CHECK:
(a)

Check the resistance.
Standard (Check for open):

Tester Connections

Specified Conditions

HT (A38–1) – HA1A (E7–2)

HT (A39–1) – HA2A (E7–1)

Below 1 

Ω

AF+ (A38–3) – A1A+ (E7–22)

AF+ (A39–3) – A2A+ (E7–23)

Below 1 

Ω

AF– (A38–4) – A1A– (E7–30)

AF– (A39–4) – A2A– (E7–31)

Below 1 

Ω

Standard (Check for short):

Tester Connections

Specified Conditions

HT (A38–1) or HA1A (E7–2) – Body ground
HT (A39–1) or HA2A (E7–1) – Body ground

10 k

Ω

 or higher

AF+ (A38–3) or A1A+ (E7–22) – Body ground
AF+ (A39–3) or A2A+ (E7–23) – Body ground

10 k

Ω

 or higher

AF– (A38–4) or A1A– (E7–30) – Body ground
AF– (A39–4) or A2A– (E7–31) – Body ground

10 k

Ω

 or higher