P2441
2TR-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
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 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 included in 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 secondary 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:
While secondary air injection ON:
While secondary air injection OFF:
TYPICAL MALFUNCTION THRESHOLDS
Condition 1:
Condition 2:
Condition 3:
Condition 4:
Condition 5:
Condition 6:
Condition 7:
Condition 8:
P2440: ASV stuck open
P2441: ASV stuck closed
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 4 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:
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.
*: 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, 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 9 to 11 kPa. The value of 2.5 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.
- When viewed from the rear of the engine assembly, Bank 1 is on the right side and Bank 2 is on the left side.
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 to OFF.
3. Connect the Techstream to the DLC3.
4. Turn the ignition switch to ON and turn the tester ON.
5. Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP: ON, ASV: OPEN and AIR PUMP: OFF, ASV: CLOSE.
HINT: When Manual Mode is selected, the tester 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 tester, indicate the conditions shown in the table below.
Standard:
*1:
Average pumping pressure (gauge pressure). The pressure should be 2.5 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 to 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 tester display indicates the prohibition (Wait or Error).
If an Error as shown in the illustration is displayed on the tester 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 to 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 tester ON.
(c) Enter the following menus: Powertrain / Engine and ECT / Trouble Codes.
(d) Read DTCs.
Result:
If any DTCs other than P2440 and/or P2441 are output, troubleshoot those DTCs first.
C -- GO TO DTC CHART
B -- GO TO AIR SWITCHING VALVE INSPECTION PROCEDURE
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 to OFF.
(3) Disconnect the No. 1 air injection system hose.
(4) Connect the Techstream to the DLC3.
(5) Turn the ignition switch to ON and turn the tester ON.
(6) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP: ON, ASV: OPEN.
HINT: When Manual Mode is selected, the tester initialization (atmospheric pressure measurement) is performed automatically. The initialization takes 10 seconds. After the initialization, AIR PUMP 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: ON, ASV: CLOSE.
(11) Check that the exhaust gas does not pulsate when the ASV is turned OFF.
(12) Turn the ignition switch to 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 tester display indicates the prohibition (Wait or Error).
If an Error is displayed on the tester 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 to OFF when the Air Injection Check operation finishes.
Standard:
(13) Reconnect the No. 1 air injection system hose.
(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 to OFF.
(3) Connect the Techstream to the DLC3.
(4) Turn the ignition switch to ON and turn the tester ON.
(5) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP: ON, ASV: OPEN and AIR PUMP: OFF, ASV: CLOSE.
(6) Start the engine after the tester 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 tester, indicate the conditions shown in the table below.
(9) Turn the ignition switch to OFF.
Result:
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.
OK -- INSPECT VACUUM HOSES (AIR SWITCHING VALVE - PRESSURE SENSOR)
NG -- Continue to next step.
3. INSPECT NO.4 INTAKE PIPE (BLOCKAGES AND LEAKAGES)
(a) Check that the No. 4 intake pipe is securely connected to both the exhaust manifold and the ASV.
(b) Inspect the No. 4 intake pipe for blockages and damage.
OK:
No blockages and damage on No. 4 intake pipe.
NG -- REPLACE NO.4 INTAKE PIPE
OK -- Continue to next step.
4. INSPECT AIR SWITCHING VALVE ASSEMBLY (AIR SWITCHING VALVE OPERATION)
(a) Check the resistance.
(1) Using an ohmmeter, measure the resistance between the terminals.
Standard Resistance:
If the result is not as specified, replace the ASV.
(b) Check the operation.
(1) Check that air does not flow from the ports.
(2) Apply the battery positive voltage across the terminals.
(3) Check that air flows from the ports.
If the operation is not as specified, replace the ASV.
OK:
ASV operates correctly
NG -- REPLACE AIR SWITCHING VALVE ASSEMBLY
OK -- Continue to next step.
5. INSPECT AIR INJECTION CONTROL DRIVER (POWER SOURCE OF AIR INJECTION CONTROL DRIVER)
(a) Disconnect the A6 and A7 AID connectors.
(b) Turn the ignition switch to ON.
(c) Measure the voltage between the terminals of the AID connector.
Standard Voltage:
(d) Check the resistance.
Standard Resistance (Check for open):
(e) Reconnect the AID connectors.
NG -- REPAIR OR REPLACE AIR INJECTION CONTROL DRIVER POWER SOURCE CIRCUIT
OK -- Continue to next step.
6. PERFORM ACTIVE TEST USING TECHSTREAM
(a) Start the engine and warm it up.
(b) Turn the ignition switch to OFF.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON and turn the tester ON.
(e) Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Manual Mode / AIR PUMP: ON, ASV: OPEN and AIR PUMP: OFF, ASV: CLOSE.
(f) Start the engine after the tester initialization is finished.
(g) Operate the AIR system using the System Check function and measure the voltage between the terminals of the ECM connector.
(h) Turn the ignition switch to OFF.
NOTICE:
- Do not perform the System Check operation repetitively. It may cause damage to the system. If necessary, leave an interval of several minutes between System Check operations.
- 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 to OFF when the Air Injection Check operation finishes.
Standard Voltage:
NG -- CHECK HARNESS AND CONNECTOR (ECM - AIR INJECTION CONTROL DRIVER)
OK -- Continue to next step.
7. REPLACE AIR INJECTION CONTROL DRIVER
NEXT -- Continue to next step.
8. CHECK WHETHER DTC OUTPUT RECURS (DTC P2440 AND/OR P2441)
(a) Start the engine and warm it up.
(b) Turn the ignition switch to OFF.
(c) Connect the Techstream to the DLC3.
(d) Turn the ignition switch to ON and turn the tester ON.
(e) Clear DTCs (if set) (DTC Check / Clear).
(f) Enter the following menus: Enter the following menus: Powertrain / Engine and ECT / Utility / Air Injection Check / Automatic Mode.
(g) Start the engine after the tester 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 to 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 to OFF when the Air Injection Check operation finishes.
NEXT -- 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. INSPECT 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 tester ON.
(d) Enter the following menus: Powertrain / Engine and ECT / Data List / Air Pump Pressure (Absolute).
(e) Check that the pressure displayed on the tester 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 tester displays the air pump pressure (Air Pump Pressure (Absolute)) as absolute pressure.
NG -- REPLACE PRESSURE SENSOR
OK -- CHECK FOR INTERMITTENT PROBLEMS
11. CHECK HARNESS AND CONNECTOR (ECM - AIR INJECTION CONTROL DRIVER)
(a) Disconnect the E4 ECM connector.
(b) Disconnect the A7 AID connector.
(c) Check the resistance.
Standard Resistance (Check for open):
(d) Reconnect the ECM and AID connectors.
NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- REPLACE ECM