2UZ-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 Sequoia)

Last Modified: 11-29-2007		1.6 C
Service Category: Engine/Hybrid System	Section: Engine Control
Model Year: 2008	Model: Sequoia	Doc ID: RM0000012FZ00HX
Title: 2UZ-FE ENGINE CONTROL: SFI SYSTEM: DESCRIPTION (2008 Sequoia)

DTC

P0418

Secondary Air Injection System Control "A" Circuit

DTC

P0419

Secondary Air Injection System Control "B" Circuit

DESCRIPTION

Refer to DTC P0412 .

DTC No.

DTC Detection Condition

Trouble Area

P0418

P0419

After cold engine starts, all of following conditions met (1 trip detection logic):

Open in air pump drive circuit
Air pump
AID
ECM

P0418

P0419

After cold engine starts, all of following conditions met (1 trip detection logic):

Short between air pump drive circuit and body ground
Air pump
AID
ECM

MONITOR DESCRIPTION

The Air Injection Control Driver (AID) detects open and short circuits according to the voltages of the air pump terminal (VP) and the Air Switching Valve (ASV) terminal (VV), and transmits diagnostic information as a signal to the ECM.

For a short time after cold engine starts, the ECM transmits command signals to the AID to drive the air pump and ASV.

The AID transmits an air pump malfunction signal to the ECM if either of the following conditions is met:

The voltage at the AID terminal relating to the air pump is low despite the AID receiving command signals from the ECM to drive the air pump.
The voltage at the AID terminal relating to the air pump is high despite the AID receiving no command signals from the ECM to drive the air pump.

The ECM sets the DTC based on diagnostic signals from the AID.

MONITOR STRATEGY

Related DTCs	P0418: Secondary air injection system air pump circuit range check (bank 1) P0419: Secondary air injection system air pump circuit range check (bank 2)
Required Sensors/Components (Main)	Air injection control driver
Required Sensors/Components (Related)	Air pump
Frequency of Operation	Once per drive cycle
Duration	3 seconds
MIL Operation	Immediate
Sequence of Operation	None

TYPICAL ENABLING CONDITIONS

Case 1

Monitor runs whenever following DTCs not present	-
Secondary air injection pump	Operating
Secondary air injection switching valve	Operating
Battery voltage	8 V or more
Ignition switch	ON
Time after ignition switch off to ON	More than 0.5 seconds
Starter	OFF
Time after starter turned from ON to OFF	More than 0.5 seconds

Case 2

Monitor runs whenever following DTCs not present	-
Secondary air injection pump	Not operating
Secondary air injection switching valve	Not operating
Battery voltage	8 V or more
Ignition switch	ON
Time after ignition switch off to ON	More than 0.5 seconds
Starter	OFF
Time after starter turned from ON to OFF	More than 0.5 seconds

TYPICAL MALFUNCTION THRESHOLDS

Diagnostic signal duty ratio from air injection control driver

11% or more, and 29% or less

COMPONENT OPERATING RANGE

Diagnostic signal duty ratio from air injection control driver

70% or more, and 90% or less when secondary air injection system operating.

0% when secondary air injection system not operating.

WIRING DIAGRAM

Refer to DTC P0412 .

INSPECTION PROCEDURE

HINT:

Diagnostic information output by the AID can be confirmed by connecting an oscilloscope to the diagnostic information terminal of the AID. Reading the waveform while performing the AIR system intrusive operation provided in the System Check function allows the possible trouble areas to be narrowed down.

NOTICE:

This Air Injection Check only allows technicians to operate the AIR system for a maximum of 5 seconds. Furthermore, the check can only be performed up to 4 times per trip. If the test is repeated, intervals of at least 30 seconds are required between checks. While AIR system operation using the Techstream is prohibited, the Techstream display indicates the prohibition (WAIT or ERROR).
If an ERROR is displayed on the Techstream during the test, stop the engine for 10 minutes, and then try again.
Performing the Air Injection Check repetitively may cause damage to the AIR system. If necessary, leave an interval of several minutes between System Check operations to prevent the system from overheating.
When performing the Air Injection Check operation after the battery cable has been reconnected, wait for 7 minutes with the ignition switch turned to ON or the engine running.
Turn the ignition switch off when the Air Injection Check operation finishes.

AID Diagnostic Signal Waveform	ECM Command	DTC (ECM Output)	Suspected Trouble Area
100% Duty Ratio	Any Secondary Air Injection (AIR) System operation	P1613 P1614	Open in diagnostic signal circuit Air Injection Control Driver (AID) Open in AID+B circuit (AID power source) Short between +B and diagnostic signal circuits
0% Duty Ratio	AIR System: ON (Air pump ON, ASV ON)	P1613 P1614	Open or short in air pump or Air Switching Valve (ASV) command signal circuit (ECM-AID) Open in AID ground circuit Short between diagnostic signal circuit and body ground AID ECM
0% Duty Ratio	AIR System: OFF (Air pump OFF, ASV OFF)	-	Normal
20% Duty Ratio	Air Pump: ON	P0418 P0419	Short between air pump drive circuit and body ground Harness and connector (AID-Pump) Air pump AID ECM
20% Duty Ratio	Air Pump: OFF	P0418 P0419	Open in air pump drive circuit (AID-Pump) Harness and connector (AID-Pump) Air pump AID ECM
40% Duty Ratio	ASV: ON	P0412 P0415	Short between ASV drive circuit and body ground Harness and connector (AID-ASV) ASV AID ECM
40% Duty Ratio	ASV: OFF	P0412 P0415	Open in ASV drive circuit (AID-ASV) Harness and connector (AID-ASV) AID ASV ECM
80% Duty Ratio	AIR System: OFF (Air pump OFF, ASV OFF)	P1613 P1614	AID ECM
80% Duty Ratio	AIR System: ON (Air pump ON, ASV ON)	-	Normal
Other than above (other than 0, 20, 40, 80 and 100% duty)	-	P1613 P1614	AID Open in AID ground circuit

HINT:

By using the Techstream to perform the Air Injection Check operation in the System Check, the air-fuel ratio and the pressure in the secondary air injection system passage can be checked while the secondary air injection system is operating. This helps technicians to troubleshoot the system when it malfunctions.
Read freeze frame data using the Techstream. Freeze frame data records 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.

PROCEDURE

1.	INSPECT AIR PUMP ASSEMBLY

(a) Disconnect the air pump connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
1 - 2	20°C (68°F)	0.44 to 1 Ω

Result

Result	Proceed to
Within standard range	A
Outside standard range (for Bank 1)	B
Outside standard range (for Bank 2)	C

2.	CHECK HARNESS AND CONNECTOR (AIR PUMP - BODY GROUND)

(a) Disconnect the air pump connector.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Condition	Specified Condition
E12-1 - Body ground	Always	Below 1 Ω
D36-1 - Body ground	Always	Below 1 Ω

3.	CHECK HARNESS AND CONNECTOR (BATTERY VOLTAGE)

(a) Disconnect the AID connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection	Condition	Specified Condition
D31-1(BATT) - Body ground	Always	11 to 14 V
D33-1(BATT) - Body ground	Always	11 to 14 V

4.	CHECK HARNESS AND CONNECTOR (AIR PUMP - AIR INJECTION CONTROL DRIVER)

(a) Disconnect the air pump connector.

(b) Disconnect the AID connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
E12-2 - D31-2(VP)	Always	Below 1 Ω
D36-2 - D33-2(VP2)	Always	Below 1 Ω
E12-2 or D31-2(VP) - Body ground	Always	10 kΩ or higher
D36-2 or D33-2(VP2) - Body ground	Always	10 kΩ or higher