Toyota Tundra Service Manual: Secondary Air Injection System Air Flow / Pressure Sensor Circuit Range / Performance Bank1 (P2431-P2433,P2436-P2438)

DESCRIPTION

The Secondary Air Injection (AIR) system consists of an air pump, the Air Switching Valve (ASV), a pressure sensor, the Air Injection Control Driver (AID) and the ECM. For a short time after a cold engine start, the AIR system pumps secondary air to the exhaust port of the cylinder head to purify the exhaust emissions. The secondary air is supplied by the air pump and is pumped to the exhaust port through the ASV.

The AID drives the ASV and the air pump according to command signals transmitted by the ECM. The pressure sensor detects the pressure in the secondary air passage when the AIR system is ON and OFF, and transmits a pressure signal to the ECM.

The AID is not only equipped to drive the pump and valve, but also has a diagnosis function to detect malfunctions in the AIR system circuit.

HINT:

As a large current is required to drive the air pump and ASV, an AID is installed to this system.

MONITOR DESCRIPTION

The ECM monitors the pressure in the secondary air passage using the pressure sensor located on the air switching valve in the secondary air injection system.

If there is a defect in the sensor or the sensor circuit, the voltage level deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the pressure sensor or circuit and stores a DTC.

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

CONFIRMATION DRIVING PATTERN

NOTICE:

• This Secondary 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 ERROR is displayed on the Techstream during the test, stop the engine for 10 minutes, and then try again.

• Performing the Secondary Air Injection Check repeatedly 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 Secondary 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 Secondary Air Injection Check operation finishes.

1. Start the engine and warm it up.
2. Turn the ignition switch off.
3. Connect the Techstream to the DLC3.
4. Turn the ignition switch to ON.
5. Turn the Techstream on.
6. Clear DTCs (if set) (See page ).
7. Turn the ignition switch off and wait for at least 30 seconds.
8. Turn the ignition switch to ON and turn the Techstream on.
9. Enter the following menus: Powertrain / Engine and ECT / Utility / Secondary Air Injection Check / Automatic Mode.
10. Start the engine after the Techstream initialization is finished.
11. Perform the System Check operation by pressing ENTER (Next).
12. Perform the following to confirm the AIR system pending codes: Press ENTER (Exit).
13. Check for pending DTCs.

    OK:

    No pending DTC is output.

14. After the "Secondary air injection check" is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.
15. Input the DTC: P2431, P2432, P2433, P2436, P2437 or P2438.
16. Check the DTC judgment result.

    Tester Display	Description
    NORMAL	DTC judgment completed System normal
    ABNORMAL	DTC judgment completed System abnormal
    INCOMPLETE	DTC judgment not completed Perform driving pattern after confirming DTC enabling conditions
    N/A	Unable to perform DTC judgment Number of DTCs which do not fulfill DTC preconditions has reached ECU memory limit

    HINT:

    • If the judgment result shows NORMAL, the system is normal.
    • If the judgment result shows ABNORMAL, the system has a malfunction.
17. If the test result is INCOMPLETE or N/A and no pending DTC is output, perform a universal trip and check for permanent DTCs (See page ).

    HINT:

    • If no permanent DTC is output, the system is normal.
    • If a permanent DTC is output, the system is malfunctioning.
18. Turn the ignition switch off.

WIRING DIAGRAM

Refer to DTC P0412 (See page ).

CAUTION / NOTICE / HINT

HINT:

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

  *: The No. 1 cylinder is the cylinder which is farthest from the transmission.

• Bank 2 refers to the bank that does not include the 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.

PROCEDURE

(a) Disconnect the air switching valve connector.

(b) Disconnect the ECM connectors.

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Air pump pressure (Absolute) and Air Pump2 Pressure (Absolute).

(e) Check the pressure displayed on the Techstream.

Standard pressure:

45 to 135 kPa

HINT:

The Techstream displays the air pump pressure as absolute pressure.

A

REPLACE ECM

B

REPLACE AIR SWITCHING VALVE ASSEMBLY (FOR BANK 1)

C

REPLACE AIR SWITCHING VALVE ASSEMBLY (FOR BANK 2)