Toyota Tundra. Manual — part 1205

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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.

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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.

1. INSPECT AIR PUMP ASSEMBLY

a. Disconnect the D56 or D57 air pump connector.

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

NG : REPLACE AIR PUMP ASSEMBLY . (See AIR PUMP ).

Fig. 143: Identifying Air Pump Connector Terminals

OK : Go to next step

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

a. Disconnect the D56 or D57 air pump connector.

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

Standard resistance (Check for open)

Tester Connection Condition Specified Condition

1 - 2

20°C (68°F)

0.44 to 1 ohms

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

TESTER CONNECTION SPECIFIED CONDITION

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

Fig. 144: Identifying D56 Or D57 Air Pump Connector Terminals

OK : Go to next step

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

a. Disconnect the D56 or D57 air pump connector.

b. Disconnect the D49 or D53 air injection control driver (AID) connector.

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

Standard resistance (Check for open)

TESTER CONNECTION SPECIFIED CONDITION

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

Tester Connection Condition Specified Condition

D56-1 - Body ground Always

Below 1 ohms

D57-1 - Body ground Always

Below 1 ohms

Tester Connection Condition Specified Condition

D56-2 - D53-2 (VP)

Always

Below 1 ohms

D57-2 - D49-2 (VP2) Always

Below 1 ohms

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

Fig. 145: Identifying D49 Or D53 Air Injection Control Driver Connector Terminals

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

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

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra

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 a 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 a DTC.

DTC TROUBLE DETECTION CONDITION CHART

HINT:

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

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

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

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

MONITOR STRATEGY

MONITOR STRATEGY

DTC

No.

DTC Detection Condition

Trouble Area

P0420

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

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Gas leakage from exhaust system

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A/F sensor (bank 1 sensor 1)

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HO2 sensor (bank 1 sensor 2)

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Exhaust pipe assembly

P0430

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

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Gas leakage from exhaust system

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A/F sensor(bank 2 sensor 1)

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HO2 sensor (bank 2 sensor 2)

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Front No. 2 exhaust pipe assembly (for
Regular Cab Standard Deck)

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Front exhaust pipe assembly (except
Regular Cab Standard Deck)

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Front No. 3 exhaust pipe sub-assembly
(except Regular Cab Standard Deck)

2008 Toyota Tundra

2008 ENGINE PERFORMANCE Engine Control System (1GR-FE) - Tundra