Toyota Sequoia (2005). Manual

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DIAGNOSTICS

ENGINE

DI–235

429

MONITOR DESCRIPTION

The air injection driver (AID) detects an open or short in the circuit according to the voltage of the air pump
terminal (VP) and electromagnetic air switching valve terminal (VV), and sends a signal as diagnostic in-
formation to the ECM.
The AID outputs the air switching valve terminal malfunction signal to the ECM if: 1) VV terminal voltage is
low despite the AID receiving the command signal from the ECM to drive the air switching valve terminal or
2) VV terminal voltage is high despite the AID not receiving the command signal from the ECM.
The ECM stores the DTC based on the diagnostic signal from the AID and illuminates the MIL.

MONITOR STRATEGY

Related DTCs

P0412

Air switching valve circuit malfunction (Second-

ary air injection system)

Required sensors/components

Air injection driver, Air switching valve

Frequency of operation

Continuous

Duration

3 sec.

MIL operation

Immediate

Sequence of operation

None

TYPICAL ENABLING CONDITIONS

Specification

Item

Minimum

Maximum

The monitor will run whenever this DTC is
not present

See page

DI–18

Case 1:

Air pump

Operating

Air switching valve

Operating

Battery voltage

8 V

–

Ignition switch

Starter

OFF

Case 2:

Air pump

Not operating

Air switching valve

Not operating

Battery voltage

8 V

–

Ignition switch

Starter

OFF

TYPICAL MALFUNCTION THRESHOLDS

Detection Criteria

Threshold

Case 1, 2:

Diagnostic signal duty ratio from air injection driver

31 to 48 %

COMPONENT OPERATING RANGE

Parameter

Standard Value

Diagnostic signal duty ratio from air injection driver

70 to 90% when secondary air injection system operating

and

0% when secondary air injection system not operating

A23551

Engine Room J/B

ECM

B–W

IA4

EB4

ED2

B–W

EFI Relay

W–B

J5
J/C

Battery

Air Pump

Air Switching Valve

Air Injection Driver

A43

A46

A41

G–R

J2
J/C

EFI No.2

EFI No.1

F10
FL Block

A40

W–L

A40

A41

W–B

BATT

SIP

SIV

R–W

G–W

GR–L

AID

AIRP

AIRV

A/PUMP

MREL

DI–236

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DIAGNOSTICS

ENGINE

430

WIRING DIAGRAM

B17411

ECM Connector

AIDI

A16555

AIR INJ CHECK

AIR PUMP............................ON
EASV ............................OPEN
ASV1. .............................OPEN
ASV2...............................OPEN
A/F BANK1.......................19.05
A/F BANK2.......................19.05
PRESSURE....................17 kPa
PULSATION..............25.39 kPa
AI STATUS...........................OK
Remaining Time 05 sec.

Press [EXIT] to quit

Example: 80% Duty Signal

5 V/DIV.

GND

20 ms/DIV.

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DIAGNOSTICS

ENGINE

DI–237

431

INSPECTION PROCEDURE

HINT:
The diagnostic information output from the AID can be confirmed by connecting an oscilloscope to the diag-
nostic information terminal of the AID. It narrows the trouble area to read the waveform on the oscilloscope
when performing the AI system intrusive operation function provided in the SYSTEM CHECK.

(1)

Start the engine and warm it up.

(2)

Turn the ignition switch to OFF.

(3)

Connect a hand–held tester to the DLC3.

(4)

Connect an oscilloscope probe to the AIDI terminal
of the ECM.

(5)

Start the engine and turn the tester ON.

(6)

On the tester, select the following menu items:
DIAGNOSIS / ENHANCED OBD II / SYSTEM
CHECK / AIR INJ CHECK / MANUAL OPERATION
/ OPERATION 1 and 2.

HINT:
OPERATION 1: AP: OFF, EASV:CLOSE, ASV1:CLOSE,
ASV2:CLOSE
OPERATION 2: AP: ON, EASV:OPEN, ASV1:OPEN,
ASV2:OPEN

(7)

Monitor the voltage output of the AID (duty ratio sig-
nal).

Oscilloscope range:

Items

Contents

Terminals

CH1: AIDI – E1

Equipment Settings

5 V/Division, 20 to 40 ms/Division

Conditions

Idling

NOTICE:

This AIR INJECTION CHECK only allows technicians to operate the AI system for 5 seconds.
Furthermore, the check can be performed 4 times a trip. If the test is repeated, intervals of at
least 30 seconds are required between checks.
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.

Performing the AIR INJ CHECK over and over again may cause the damage in the secondary
air injection system. If necessary, put an interval of several minutes between tests to prevent
overheating the system.

A23464

AID Diagnostic Signal Waveforms

ECM

Commands

DTCs

Suspected Trouble Areas

(ECM Output)

100 % Duty ratio

Almost Battery Voltage

GND

0 % Duty ratio

Fixed at Low Voltage

GND

20 % Duty ratio

20 %

GND

40 % Duty ratio

40 %

GND

80 % Duty ratio

80 %

GND

Excluding above
(excluding 0, 20, 40, 80, 100 % duty)

Air Pump: ON

Air Pump: OFF

ASV: ON

ASV: OFF

AI System: OFF

(Air pump OFF,

ASV OFF)

AI System: ON

(Air pump ON,

ASV ON)

P1613

P0418

P0412

P1613

Air Injection Control Driver (AID)

Open in AID+B circuit (AID power source)

Open or short in air pump or Air Switching Valve

AID
ECM

Open in air pump drive circuit (AID–Pump) ,

Harness & connector (AID–Pump)
Air Pump

AID

ECM

Short between air pump drive circuit and body ground

AID
ECM

Harness & connector (AID–Pump)
Air Pump

Open in ASV drive circuit (AID–ASV),

Harness & connector (AID–ASV)
ASV
AID

ECM

Short between ASV drive circuit and body ground

Harness & connector (AID–ASV)

AID

ECM

Normal

AID

or short between air pump drive circuit and +B

or short between ASV drive circuit and +B



ASV

–

AI System: OFF

(Air pump OFF,

ASV OFF)

AI System: ON

(Air pump ON,

ASV ON)

Normal

Any Air Injection

(AI) System op-

eration

P1613

Open in AID ground circuit

Short between +B circuit and diagnostic signal circuit

Short between diagnostic signal circuit and body

(ASV) command signal circuit (ECM–AID)

ground

Open in AID ground circuit

Open in diagnostic signal circuit

DI–238

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DIAGNOSTICS

ENGINE

432

Toyota Sequoia (2005). Manual - part 108