Toyota Tundra. Manual — part 1381

B : REPLACE AIR PUMP ASSEMBLY (for Bank 1) . (See AIR PUMP (FOR BANK 1) ).

C : REPLACE AIR PUMP ASSEMBLY (for Bank 2) (See AIR PUMP (FOR BANK 2) ).

Fig. 146: Identifying Air Pump Connector Terminal

A : Go To Next Step

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

a. Disconnect the E10 or D57 air pump connector.

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION

Result

Proceed To

OK

A

NG (for Bank 1)

B

NG (for Bank 2)

C

Tester Connection Condition Specified Condition

E10-1 - Body ground Always

Below 1 ohms

D57-1 - Body ground Always

Below 1 ohms

2008 Toyota Tundra

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

Fig. 147: Identifying E10 Or D57 Air Pump Connector Terminal

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : Go To Next Step

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

a. Disconnect the E10 or D57 air pump connector.

b. Disconnect the D48 or D52 AID connector.

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

Standard resistance

STANDARD RESISTANCE SPECIFICATION

Tester Connections Condition Specified Conditions

E10-2 - D48-2 (VP)

Always

Below 1 ohms

D57-2 - D52-2 (VP2) Always

Below 1 ohms

2008 Toyota Tundra

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

Fig. 148: Identifying Air Pump & Air Injection Control Driver Connector Terminal

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : REPLACE AIR INJECTION CONTROL DRIVER . (See AIR INJECTION DRIVER ).

DTC P0420 CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 1); DTC P0430
CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD (BANK 2)

MONITOR DESCRIPTION

2008 Toyota Tundra

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

The ECM uses sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor
its efficiency.

The first sensor, the Air-Fuel Ratio (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor,
the Heated Oxygen (HO2) sensor, sends post-catalyst information to the ECM. In order to detect any
deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This
calculation is based on the voltage output of the HO2 sensor while performing active air-fuel ratio control.

The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven
with a warm engine, active air-fuel ratio control is performed for approximately 15 to 20 seconds. When it is
performed, the ECM deliberately sets the air-fuel ratio to lean or rich levels. If the rich-lean cycle of the HO2
sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and
the TWC.

The ECM uses the OSC value to determine the state of the TWC. If any deterioration has occurred, it
illuminates the MIL and sets the DTC.

DTC DETECTION CONDITION AND TROUBLE AREA

HINT:



Bank 1 refers to the bank that includes No. 1 cylinder.



Bank 2 refers to the bank that does not include No. 1 cylinder.



Sensor 1 refers to the sensor closest to the engine assembly.



Sensor 2 refers to the sensor farthest away from the engine assembly.

MONITOR STRATEGY

MONITOR STRATEGY

DTC

Code

DTC Detection Condition

Trouble Area

P0420

OSC value smaller than standard value under active
air-fuel ratio control
(2 trip detection logic)



Gas leakage from exhaust system



Air-Fuel Ratio (A/F) sensor (for
bank 1 sensor 1)



Heated Oxygen (HO2) sensor (for
bank 1 sensor 2)



Front No. 2 exhaust pipe assembly

P0430

OSC value smaller than standard value under active
air-fuel ratio control
(2 trip detection logic)



Gas leakage from exhaust system



Air-Fuel Ratio (A/F) sensor (for
bank 2 sensor 1)



Heated Oxygen (HO2) sensor (for
bank 2 sensor 2)



Front exhaust pipe assembly

P0420: Catalyst Deterioration (bank 1)

2008 Toyota Tundra

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