P2437

1UR-FE ENGINE CONTROL: SFI SYSTEM: P2431-P2433,P2436-P2438: Secondary Air Injection System Air Flow / Pressure Sensor Circuit Range / Performance Bank1
P2438 - Secondary Air Injection System Air Flow / Pressure Sensor Circuit High Bank 2

DESCRIPTION

The secondary air injection system injects air into the exhaust port of the cylinder head using an electric air pump, starting when the engine is started cold and operating until the catalyst warms up, in order to promote combustion of unburned fuel and decrease the amount of hydrocarbons (HC) and carbon monoxide (CO) in the exhaust gas.





The ECM operates the air injection VSV relay (AI-VSV) which causes the air switching valve (for bank 2) to operate.





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. Using this pressure value, the ECM determines whether the secondary air injection system is malfunctioning or not.

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

P2431 and P2436





P2432, P2433, P2437 and P2438





TYPICAL MALFUNCTION THRESHOLDS

P2431 and P2436





P2432 and P2437





P2433 and P2438





COMPONENT OPERATING RANGE





CONFIRMATION DRIVING PATTERN

NOTICE:
- This Air Injection Check only allows technicians to operate the secondary air injection 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 secondary air injection 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 Air Injection Check repeatedly may cause damage to the secondary air injection system. If it is necessary to repeat the check, 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 engine switch turned on (IG) or the engine running.
- Turn the engine switch off when the Air Injection Check operation finishes.
- Start the engine and warm it up.

- Turn the engine switch off.

- Connect the Techstream to the DLC3.

- Turn the engine switch on (IG).

- Turn the Techstream on.

- Clear DTCs (even if no DTCs are stored, perform the clear DTC operation) DTC Check / Clear.

- Turn the engine switch off and wait for at least 30 seconds.

- Turn the engine switch on (IG) and turn the Techstream on.

- Enter the following menus: Powertrain / Engine and ECT / Utility / Air injection check / Automatic Mode.

- Start the engine after the Techstream initialization is finished.

- Perform the System Check operation by pressing ENTER (Next).

- Perform the following to confirm the secondary air injection system pending codes: Press ENTER (Exit).

- Check for pending DTCs.

OK:

No pending DTC is output.

- After "Air injection check" is completed, check for All Readiness by entering the following menus: Powertrain / Engine and ECT / Utility / All Readiness.

- Input the DTC: P2431, P2432, P2433, P2436, P2437 or P2438.

- Check the DTC judgment result.





HINT
- If the judgment result shows NORMAL, the system is normal.
- If the judgment result shows ABNORMAL, the system has a malfunction.
- If the judgment result is INCOMPLETE or UNKNOWN and no pending DTC is output, perform a universal trip and check for permanent DTCs DTC Check / Clear.

HINT
- If no permanent DTC is output, the system is normal.
- If a permanent DTC is output, the system is malfunctioning.
- Turn the engine switch off.

WIRING DIAGRAM





INSPECTION PROCEDURE

HINT
- Refer to "Data List / Active Test" [Air Pump Pressure (Absolute) and Air Pump2 Pressure (Absolute)] Data List / Active Test.
- 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.
PROCEDURE

1. CHECK HARNESS AND CONNECTOR (PRESSURE SENSOR - ECM)

(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 -- Continue to next step.

2. CHECK TERMINAL VOLTAGE (VC OF AIR SWITCHING VALVE)





(a) Disconnect the air switching valve connector.

(b) Turn the engine switch on (IG).

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

Standard Resistance:





Text in Illustration





NG -- REPLACE ECM Removal
OK -- Continue to next step.

3. REPLACE AIR SWITCHING VALVE ASSEMBLY

(a) Replace the air switching valve assembly.

HINT
- Replace the air switching valve assembly for bank 1 Removal.
- Replace the air switching valve assembly for bank 2 Removal.
NEXT -- Continue to next step.

4. CHECK WHETHER DTC OUTPUT RECURS

(a) Perform the Confirmation Driving Pattern.

Result





B -- REPLACE ECM Removal

A -- END