P2440

DTC P2440 SECONDARY AIR INJECTION SYSTEM SWITCHING VALVE STUCK OPEN (BANK1)

1. OUTLINE OF DIAGNOSIS
Detect NG judging from secondary air delivery pipe pressure, pulse of secondary air delivery pipe pressure and secondary air pipe airflow amount.

2. ENABLE CONDITION






3. GENERAL DRIVING CYCLE
Perform diagnosis during secondary air pump operation

4. DIAGNOSTIC METHOD
Measure secondary air delivery pipe pressure, pulse of secondary air delivery pipe pressure and secondary air pipe airflow amount.






Pump supply pressure check
Perform the system function diagnosis with how much the pressure rises when the secondary air pump is turned from OFF to ON.
Judge as NG if delivery pipe pressure does not rise though it should when the secondary air pump turns OFF -> ON.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 2000 ms + 2800 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 2000 ms + 2800 ms

Combination valve one side closed pulse diagnosis
Perform close stuck diagnosis of the LH combination valve using delivery pipe pressure pulse when the RH combination valve is closed.
Calculate the voltage pulse of the pump delivery pipe pressure when the RH combination valve is closed and the LH combination valve is open. The calculation of delivery pipe pressure should be large when the LH combination valve is open. Judge that the LH combination valve is close stuck if the calculation is small.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Perform close stuck diagnosis of the RH combination valve using delivery pipe pressure pulse when the LH combination valve is closed.
Calculate the voltage pulse of the pump delivery pipe pressure when the LH combination valve is closed and the RH combination valve is open. The calculation of delivery pipe pressure should be large when the RH combination valve is open. Judge that the RH combination valve is close stuck if the calculation is small.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Combination valve both closed pulse diagnosis
Perform open stuck diagnosis of both combination valves using delivery pipe pressure pulse when both combination valves are closed. Determine which side of valves is stuck open by comparing secondary air flow amount when RH combination valve is closed with that when LH combination valve is closed.
Calculate voltage pulse of the pump delivery pipe pressure when both combination valves are closed. The calculation should be small because there is no pulse from supply pipe pressure with both combination valves closed. When the calculation is large, determine that either of the combination valves is stuck open. Determine which side of valves is stuck open by comparing secondary air flow amount when the RH combination valve is closed with that when the LH combination valve is closed. Air flow amount is larger on the open stuck valve.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Combination valve changeover pressure diagnosis
Perform the RH combination valve stuck closed diagnosis with the variation of delivery pipe pressure when the RH combination valve turns closed -> open.
Delivery pipe pressure should vary when the RH combination valve turns closed -> open. When the variation is small, determine that the RH combination valve is stuck closed.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Perform the LH combination valve stuck closed diagnosis with the variation of delivery pipe pressure when the LH combination valve turns open -> closed.
Delivery pipe pressure should vary when the LH combination valve turns open -> closed. When the variation is small, determine that the LH combination valve is stuck closed.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Overflow diagnosis
Perform secondary air system flow abnormality diagnosis using both sides of combination valves secondary air amount when both are closed.
Judge as secondary air system flow abnormality either if there is excessive secondary air flow amount with the RH combination valve closed, or if there is excessive secondary air flow amount with the LH combination valve closed.

- Abnormality Judgment
If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

- Normality Judgment
Judge as OK and clear the NG if the continuous time while the following conditions are established is more than the predetermined time.






Time Needed for Diagnosis: 4000 ms + 992 ms + 992 ms + 992 ms

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