Toyota Sequoia (2005). Manual - part 109

B17440

A46

Air Switching Valve Connector

Wire Harness Side:

–

DIAGNOSTICS

ENGINE

DI–239

433

HINT:

Using the AIR INJ CHECK operation of the SYSTEM CHECK provided in the hand–held tester func-
tion, conditions for air–fuel ratio and pressure in the secondary air injection system passage can be
checked while the secondary air injection system operating. It helps technicians to troubleshoot the
system when it malfunctioning.

Read freeze frame data using a hand–held tester. Freeze frame data record the engine condition when
malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle
was moving or stationary, if the engine was warmed up or not, if the air–fuel ratio was lean or rich, and
other data, from the time the malfunction occurred.

1

Check voltage between terminal 1 of air switching valve connector and body
ground.

PREPARATION:
(a)

Remove the intake manifold (see page 

EM–36

).

(b)

Disconnect the A46 air switching valve connector.

(c)

Connect the hand–held tester to the DLC3.

(d)

Turn the ignition switch ON and turn the tester ON.

CHECK:
(a)

When the air switching valve is operated using the hand–
held tester, measure voltage between terminal A46–1 of
the air switching valve connector and body ground.

(b)

Select the following menu items: DIAGNOSIS/EN-
HANCED OBD II/SYSTEM CHECK/ AIR INJ CHECK/
MANUAL OPERATION/OPERATION 1 and 4

HINT:
OPERATION 1: AP:OFF, EASV:CLOSE, ASV1:CLOSE,
ASV2:CLOSE
OPERATION  4: AP:OFF,  EASV:OPEN, ASV1:CLOSE,
ASV2:CLOSE
NOTICE:
This test only allows technicians to operate the AI system
for 5 seconds. Furthermore, the test can be performed 4
times a trip. If the test is repeated, intervals of at least 30
seconds are required between tests.
While the AI system operation using the hand–held tester
is prohibited, the tester displays the prohibition (WAIT or
ERROR). If the ERROR (AI STATUS NG) is displayed on the
tester, stop the engine for 10 minutes and then try again..
OK:

Standard:

Tester operation

Tester Connection

Specified Condition

Operation 4

A46–1 – Body ground

10 V or more

Operation 1

A46–1 – Body ground

Below 1.0 V

NG

Go to step 4.

OK

A23465

Component Side:

ASV Connector

Front View

A46

B17440

A46

Air Switching Valve Connector

Wire Harness Side:

DI–240

–

DIAGNOSTICS

ENGINE

434

2

Check air switching valve.

(a)

Remove the intake manifold (see page 

EM–36

).

(b)

Disconnect the ASV connector.

(c)

Measure the resistance of the ASV.
Standard:

Tester Connections

Specified Conditions

A46–1 – A46–2

4.5 to 5.5 

Ω

NG

 Replace air switching valve.

OK

3

Check for open in harness and connector between air switching valve and body
ground.

PREPARATION:
(a)

Remove the intake manifold (see page 

EM–36

).

(b)

Disconnect the A46 air switching valve connector.

CHECK:
Measure the resistance between the wire harness side connec-
tors and body ground.
OK:

Standard:

Tester Connection

Specified Condition

A46–2 – Body ground

Below 1 

Ω

NG

Repair or replace harness or connector.

OK

Check for intermittent problems 
(See page 

DI–11

).

B17444

Wire Harness Side:

Air Injection Driver Connector

A41

VV

B17440

A46

Air Switching Valve Connector

Wire Harness Side:

–

DIAGNOSTICS

ENGINE

DI–241

435

4

Check for open and short in harness and connector between air injection driver
and air switching valve.

PREPARATION:
(a)

Remove the intake manifold (see page 

EM–36

).

(b)

Disconnect the A41 air injection driver connector.

(c)

Disconnect the A46 air switching valve connector.

CHECK:
Measure the resistance between the wire harness side connec-
tors.
OK:

Standard:

Tester Connection

Specified Condition

VV (A41–6) – A46–1

Below 1 

Ω

VV (A41–6) or A46–1 – 

Body ground

10 k

Ω

 or higher

NG

Repair or replace harness or connector.

OK

Replace air injection driver.

DI–242

–

DIAGNOSTICS

ENGINE

436

DTC

P0418

Air Injection System Air Pump Malfunction

CIRCUIT DESCRIPTION

Refer to DTC P0412 on page 

DI–234

.

DTC No.

DTC Detection Condition

Trouble Area

P0418

All of the following conditions are met, when idling just after

cold start. (1 trip detection logic):

(a) Air injection system not operate

(b) Air injection driver outputs air pump malfunction signal (20%

duty signal)

Open in air pump drive circuit

Short between air pump circuit and +B circuit

Air injection driver

ECM

P0418

All of the following conditions are met, when idling just after

cold start. 

(1 trip detection logic):

(a) Air injection system operates

(b) Air injection driver outputs air pump malfunction signal (20%

duty signal)

Short between air pump circuit and body ground

Air injection driver

ECM

MONITOR DESCRIPTION

Air Injection Driver (AID) detects an open or short in the air pump and Air Switching Valve (ASV) circuit ac-
cording to the terminal voltage and sends a signal as diagnostic information to the ECM.
When the air injection system operation is required while the engine is warming up, the ECM transmits com-
mand signals to the AID to drive the air pump and ASV.
The AID inputs the command signal from ECM if: 1) VP terminal voltage is low despite the AID inputting the
command signal from the ECM to drive the ASV or 2) VP terminal voltage is high despite the AID not inputting
the command signal from the ECM.
The ECM sets the DTC based on the diagnostic information from the AID.

MONITOR STRATEGY

Related DTCs

P0418

Air pump range check

Required sensors/components

Air injection driver, Air pump

Frequency of operation

Continuous

Duration

3 sec.

MIL operation

Immediate

Sequence of operation

None

DIDMW–01