P2446
DTC P2444 Secondary Air Injection System Pump Stuck On Bank1DTC P2445 Secondary Air Injection System Pump Stuck Off Bank1
DTC P2446 Secondary Air Injection System Pump Stuck On Bank 2
DTC P2447 Secondary Air Injection System Pump Stuck Off Bank 2
DESCRIPTION
DTC Detection Condition:
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.
MONITOR DESCRIPTION
Monitor Strategy (Part 1):
Monitor Strategy (Part 2):
Typical Enabling Conditions:
Typical Malfunction Thresholds (Part 1):
Typical Malfunction Thresholds (Part 2):
The ECM monitors the pressure in the secondary air passage using the pressure sensor located on the Air Switching Valve (ASV) of the Secondary Air Injection (AIR) system. The sensor measures the pressure in the secondary air passage and transmits a signal to the ECM.
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:
- The pressure indicated by the pressure sensor does not reach threshold levels despite the ECM turning on the air pump.
- The pressure indicated by the pressure sensor exceeds threshold levels despite the ECM turning off the air pump.
MONITOR RESULT
Refer to CHECKING MONITOR STATUS Checking Monitor Status
Wiring Diagram (Part 1):
Wiring Diagram (Part 2):
Step 1:
Step 1(Continued)-2:
Step 2(Continued)-3:
Step 3(Continued)-5:
Step 6:
Step 7:
Step 8:
Step 8(Continued)-10:
Step 11:
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.
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 2.4 kPa indicated in the table 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 intelligent tester or Techstream to perform the AIR INJ CHECK.1 (Air Injection Check.2) 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 SYSTEM CHECK / AIR INJ CHECK / AUTOMATIC.1 (Utility / Air Injection Check / Automatic Mode).2 after the repair.
*1: Intelligent tester
*2: Techstream
- Read freeze frame data using the intelligent tester or 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 intelligent tester or Techstream.
a. Start the engine and warm it up.
b. Turn the ignition switch OFF.
c. Connect the intelligent tester or Techstream to the DLC3.
d. Turn the ignition switch ON and turn the tester ON.
e. Enter the following menus:
1. Intelligent tester - Select: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / AIR INJ CHECK / MANUAL / AP1: ON, ASV1: OPEN, AP2: ON, ASV2: OPEN and AP1: OFF, ASV1 CLOSE, AP2: OFF, ASV2 CLOSE.
2. Techstream - Select: 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 (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.
f. Start the engine.
g. Perform the AIR system intrusive operation while the engine is idling.
h. 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.
i. Turn the ignition switch OFF.
NOTE:
- This AIR INJ CHECK (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.
Wile AIR system operation using the intelligent tester or 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 INJ CHECK (Air Injection Check) repetitively 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 INJ CHECK (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 INJ CHECK (Air Injection Check) operation finishes.