Toyota Tundra. Manual — part 1426

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 2

Condition 3:

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 3

Condition 4:

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 4

Condition 5:

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 5

Condition 6:

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 6

Condition 7:

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 7

Condition 8:

TYPICAL MALFUNCTION THRESHOLDS - CONDITION 8

Case 1:

TYPICAL MALFUNCTION THRESHOLDS - CASE 1

Case 2:

TYPICAL MALFUNCTION THRESHOLDS - CASE 2

AIR pressure during AIR ON

Less than 1 kPa and pulse is generated

AIR pressure during AIR ON

1 kPa or more and pulse is not generated

AIR pressure during AIR ON

Less than 1 kPa and pulse is not generated

AIR pressure during AIR OFF

5 kPa or more and pulse is generated

AIR pressure during AIR OFF

Less than 5 kPa and pulse is generated

AIR pressure during AIR OFF

5 kPa or more and pulse is not generated

AIR pressure during AIR OFF

Less than 5 kPa and pulse is not generated

Any of following conditions met:

(a), (b) or (c)

(a) Conditions 1 and 6

Met

(b) Conditions 1 and 5

Met

(c) Conditions 2 and 6

Met

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Case 3:

TYPICAL MALFUNCTION THRESHOLDS - CASE 3

MONITOR RESULT

Refer to CHECKING MONITOR STATUS .

WIRING DIAGRAM

Refer to DTC P0412 .

INSPECTION PROCEDURE

HINT:

Determination by ECM monitoring:

The ECM locates malfunctions in the Secondary Air Injection (AIR) system by detecting the pressure in the
AIR passage between the air pump and Air Switching Valve (ASV) and sets a DTC. Soon after cold engine
starts, the monitor runs for a short time while the AIR system is both ON and OFF. The ECM detects both the
pressure and the exhaust pulsation and compares them.

The following 8 patterns are AIR system pressure conditions in the AIR system passage.

Pressure Condition in Secondary Air Injection System Case 1:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 1

Pressure Condition in Secondary Air Injection System Case 2:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 2

Any of following conditions met:

(a), (b) or (c)

(a) Conditions 3 and 7

Met

(b) Conditions 3 and 8

Met

(c) Conditions 4 and 8

Met

Cumulative pressure pulsation

100 kPa or more

Air Pump

ON

Air Switching Valve

Open

Pressure

1 kPa or more

Pulsation Detection

Exhaust gas pulsation detected

Air Pump

OFF

Air Switching Valve

Open

Pressure

Less than 1 kPa

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

Pressure Condition in Secondary Air Injection System Case 3:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 3

Pressure Condition in Secondary Air Injection System Case 4:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 4

Pressure Condition in Secondary Air Injection System Case 5:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 5

Pressure Condition in Secondary Air Injection System Case 6:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 6

Pressure Condition in Secondary Air Injection System Case 7:

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 7

Pressure Condition in Secondary Air Injection System Case 8:

Pulsation Detection

Exhaust gas pulsation detected

Air Pump

ON

Air Switching Valve

Closed

Pressure

1 kPa or more

Pulsation Detection

Exhaust gas pulsation not detected

Air Pump

OFF

Air Switching Valve

Close

Pressure

Less than 1 kPa

Pulsation Detection

Exhaust gas pulsation not detected

Air Pump

ON

Air Switching Valve

Open

Pressure

5 kPa or more

Pulsation Detection

Exhaust gas pulsation detected

Air Pump

OFF

Air Switching Valve

Open

Pressure

Less than 5 kPa

Pulsation Detection

Exhaust gas pulsation detected

Air Pump

ON

Air Switching Valve

Closed

Pressure

5 kPa or more

Pulsation Detection

Exhaust gas pulsation not detected

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra

PRESSURE CONDITION IN SECONDARY AIR INJECTION SYSTEM CASE 8

If the detected pressure is high, the air pump is assumed to be ON and if it alternates sharply, the ASV is
assumed to be open. The ECM locates malfunctions from the combination of pressures detected when the AIR
system is ON and OFF.

HINT:

The exhaust pulsation value is calculated in the ECM. If the calculated value exceeds a certain level, the ECM
determines that the exhaust pulsation is in the AIR system.

HINT:



In case 3 and 7, as the pressure sensor detects a slight pump operation pulsation, the detected value is not
constant. Since the pump outlet is blocked by closing the ASV, the average pressure is higher than in case
1 (approximately 20 to 30 kPa).



In case 1, the average pressure is approximately 3 to 11 kPa. The value of 1 kPa indicated in the table
above is a threshold for detecting pump malfunctions.

DTC CHART

Air Pump

OFF

Air Switching Valve

Close

Pressure

Less than 5 kPa

Pulsation Detection

Exhaust gas pulsation not detected

Detected Conditions while

AIR operating: Air pump

ON, ASV Open

Detected Conditions while

AIR not operating: Air pump

OFF, ASV Closed

ECM Determination

DTCs Output

Case 1

Case 8

Normal

-

Case 1

Case 6

ASV stuck open

P2440 or P2442

Case 1

Case 7

Air pump stuck ON

P2444 or P2446

Case 2

Case 8

Air pump stuck OFF

P2445 or P2447

Case 3

Case 8

ASV stuck closed

P2441 or P2443

Case 1

Case 5

ASV stuck open and air
pump stuck ON

P2440 and

P2444 or P2442

and P2446

Case 2

Case 6

ASV stuck open and air
pump stuck OFF

P2440 and

P2445 or P2442

and P2447

Case 3

Case 7

ASV stuck closed and
air pump stuck ON

P2441 and

P2444 or P2443

and P2446

Case 4

Case 8

ASV stuck closed and
air pump stuck OFF

P2441 and

P2445 or P2443

and P2447

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (2UZ-FE) - Tundra