P2441

2UZ-FE ENGINE CONTROL SYSTEM: SFI SYSTEM: P2440: Secondary Air Injection System Switching Valve Stuck Open Bank1

DTC P2440 - Secondary Air Injection System Switching Valve Stuck Open Bank1

DTC P2441 - Secondary Air Injection System Switching Valve Stuck Close Bank1

DTC P2442 - Secondary Air Injection System Switching Valve Stuck Open Bank 2

DTC P2443 - Secondary Air Injection System Switching Valve Stuck Closed Bank 2

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 cold engine starts, 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 with 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.









HINT: Air switching valve normal operation:
When the Air Switching Valve (ASV) is open, exhaust gas pulsation occurs in the secondary air passage.
When the ASV is closed, exhaust gas pulsation does not occur in the secondary air passage.

MONITOR DESCRIPTION

The ECM monitors the pressure in the secondary air passage using the pressure sensor connected to the ASV of the Secondary Air Injection (AIR) system.
If either of the following conditions occurs, the ECM interprets it as a malfunction of the AIR system, and illuminates the MIL and sets a DTC:

- Exhaust gas pulsation is detected by the pressure sensor despite the ECM commanding the ASV to close.
- Exhaust gas pulsation is not detected by the pressure sensor despite the ECM commanding the ASV to open.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

All:





Case 1:





Case 2:





Case 3:





TYPICAL MALFUNCTION THRESHOLDS

Condition 1:





Condition 2:





Condition 3:





Condition 4:





Condition 5:





Condition 6:





Condition 7:





Condition 8:





Case 1:





Case 2:





Case 3:





MONITOR RESULT

Refer to Checking Monitor Status Mode 6 Data.

WIRING DIAGRAM









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 2:





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 5:





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 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.





HINT:
- If the vacuum hose between the ASV and the pressure sensor is not connected correctly, case 4 may occur.
- 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. Furthermore, Pending Codes also can be checked by performing Utility / Air Injection Check / Automatic Mode after the repair.
- 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.
- System Check:
- The pressure in the secondary air passage can be checked using the Techstream.
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 and turn the Techstream ON.
5. Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP 1: ON, ASV1: OPEN, AIR PUMP 2: ON, ASV2: OPEN and AIR PUMP 1: OFF, ASV1 CLOSE, AIR PUMP 2: OFF, ASV2 CLOSE.
HINT: When Manual Mode is selected, the Techstream initialization (atmospheric pressure measurement) is performed automatically. The initialization takes 10 seconds. After the initialization, AIR PUMP and ASV operation can be selected.

6. Start the engine.
7. Perform the AIR system intrusive operation while the engine is idling.
8 Check that the air pump (AIR PUMP), ASV and pressure in the AIR system passage (PRESSURE) displayed on the Techstream indicate the conditions shown in the table below.
Standard:






*1:
Average pumping pressure (gauge pressure). The pressure should be 1 kPa or more when the AIR system operates.
*2:
The cumulative exhaust pulsation calculated by the ECM. If the calculated value exceeds a certain level, the ECM determines that the exhaust pulsation is in the AIR system.
9. Turn the ignition switch off.
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 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 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.

PROCEDURE

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO SECONDARY AIR INJECTION SYSTEM DTCS)
(a) Connect the Techstream to the DLC3.
(b) Turn the ignition switch to ON and turn the Techstream ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(d) Read DTCs.

Result





If any DTCs other than P0412, P0415, P2440, P2441, P2442 and/or P2443 are output, troubleshoot those DTCs first.
C -- GO TO DTC CHART
B -- GO TO AIR SWITCHING VALVE INSPECTION PROCEDURE (P0412 AND P0415)
A -- Continue to next step.
2. PERFORM ACTIVE TEST USING TECHSTREAM




(a) Visual check
(1) Start the engine and warm it up.
(2) Turn the ignition switch off.
(3) Disconnect the No. 2 air injection system hose and No. 2 air hose.
(4) Connect the Techstream to the DLC3.
(5) Turn the ignition switch to ON and turn the Techstream ON.
(6) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP 1: ON, ASV1: OPEN, AIR PUMP 2: ON, ASV2: OPEN.
HINT: When Manual Mode is selected, the Techstream initialization (atmospheric pressure measurement) is performed automatically. The initialization takes 10 seconds. After the initialization, AP and ASV operation can be selected.

(7) Start the engine.
(8) Perform the AIR system intrusive operation while the engine is idling.
(9) Place your hand near the air switching valve port and check that the exhaust gas pressure pulsates when the ASV is turned ON.
CAUTION: To avoid the danger of being burned by the exhaust gas, bring your hand close to the valve port slowly.

(10) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP 1: ON, ASV1: OPEN, AIR PUMP 2: ON, ASV2: OPEN and AIR PUMP 1: ON, ASV1: CLOSE, AIR PUMP 2: ON, ASV2: CLOSE.
(11) Check that the exhaust gas does not pulsate when the ASV is turned OFF.
(12) Turn the ignition switch off.
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 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 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.

Standard:





(b) Other inspection method:
The ASV operation can be confirmed by checking the cumulative pressure pulsation* provided in the System Check.
Perform System Check operation under Manual Mode.
*: 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.
(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 and turn the Techstream ON.
(5) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP 1: ON, ASV1: OPEN, AIR PUMP 2: ON, ASV2: OPEN and AIR PUMP 1: OFF, ASV1: CLOSE, AIR PUMP 2: OFF, ASV2: CLOSE.
(6) Start the engine after the Techstream initialization is finished.
(7) Perform the AIR system intrusive operation while the engine is idling.
(8) Check that the air-fuel ratio and pressure in the secondary air injection system passage (PULSATION) displayed on the Techstream indicate the conditions shown in the table below.
(9) Turn the ignition switch off.
OK:






Reference:
If the air pump operation is confirmed as normal P2444, the air-fuel ratio detected in front of three-way catalytic converter changes in response to the secondary air pumped into the exhaust port when the air pump operates.

Result





B -- INSPECT VACUUM HOSES (AIR SWITCHING VALVE - PRESSURE SENSOR)
A -- Continue to next step.
3. INSPECT AIR TUBE (BLOCKAGES AND LEAKAGES)




(a) Check that the No. 2 and No. 3 air tubes are securely connected to both the exhaust manifold and the ASV.
(b) Inspect the air tube for blockages and damage.
OK:
No blockages and damage on intake pipe.

Result





C -- REPLACE AIR TUBE
B -- REPLACE AIR TUBE
A -- Continue to next step.
4. INSPECT AIR SWITCHING VALVE
(a) Inspect the air switching valve for Bank 1 Air Switching Valve (for Bank 1).
(b) Inspect the air switching valve for Bank 2 Air Switching Valve (for Bank 2).

Result





C -- REPLACE AIR SWITCHING VALVE
B -- REPLACE AIR SWITCHING VALVE
A -- Continue to next step.
5. INSPECT AIR INJECTION CONTROL DRIVER (POWER SOURCE OF AIR INJECTION CONTROL DRIVER)




(a) Disconnect the D48 and D50 or D52 and D54 AID connectors.
(b) Turn the ignition switch to ON.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:





(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE AIR INJECTION CONTROL DRIVER POWER SOURCE CIRCUIT
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (ECM - AIR INJECTION CONTROL DRIVER)




(a) Disconnect the A24 or D74 ECM connector.
(b) Disconnect the D50 or D54 AID connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. REPLACE AIR INJECTION CONTROL DRIVER
(a) Replace the air injection control driver Removal.
NEXT -- Continue to next step.
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2440, P2441, P2442 AND/OR P2443)
(a) Start the engine and warm it up.
(b) Turn the ignition switch off.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON and turn the Techstream ON.
(e) Clear DTCs (if set) DTC Check / Clear.
(f) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Automatic Mode.
(g) Start the engine after the Techstream initialization is finished.
(h) Perform the System Check operation by pressing Next.
(i) After operating the AIR system, perform the following to confirm the AIR system pending codes: Press the Exit button.
(j) Check pending DTCs.
(k) Turn the ignition switch off.
OK:
No pending DTC output.
NOTICE:
- 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.

NG -- REPLACE ECM
OK -- END
9. INSPECT VACUUM HOSES (AIR SWITCHING VALVE - PRESSURE SENSOR)
OK:
No blockage and no deformation in vacuum hose.
NG -- REPAIR OR REPLACE VACUUM HOSE
OK -- Continue to next step.
10. READ VALUE USING AIR SWITCHING VALVE (PRESSURE SENSOR)




(a) Connect a pressure gauge to the air pressure sensor as shown in the illustration.
(b) Connect the Techstream to the DLC3.
(c) Turn the ignition switch to ON and 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 that the pressure displayed on the Techstream fluctuates when applying pressure to the pressure sensor with the pressure gauge.
OK:
Pressure fluctuates in response to pressure applied with pressure gauge.
HINT: The Techstream displays the air pump pressure as absolute pressure.

Result





C -- REPLACE AIR SWITCHING VALVE
B -- REPLACE AIR SWITCHING VALVE
A -- CHECK FOR INTERMITTENT PROBLEMS