Sfi System - P0412

Brand:

Toyota

Model Name:

4Runner GRN210 215 UZN210 215

Manual:

Repair Manual

Section:

2Uz-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Monitor description

  3. Monitor strategy

  4. Typical enabling conditions

  5. Typical malfunction thresholds

  6. Component operating range

  7. Wiring diagram

  8. Inspection procedure

  9. Inspect air switching valve

  10. Check harness and connector (air switching valve - body ground)

  11. Check harness and connector (air switching valve - air injection control driver)

DTC P0412 Secondary Air Injection System Switching Valve "A" Circuit


​

DESCRIPTION

The Secondary Air Injection (AIR) system pumps air to the exhaust port to accelerate the activation of the catalyst. The secondary air injection system consists of the ECM, air pump, Air Switching Valve (ASV) (EASV), No. 2 Air Switching Valve (No. 2 ASV) (ASV1, 2), pressure sensor and Air Injection Control Driver (AID). The Air Switching Valve (ASV) (EASV) is an electromagnetic type and No. 2 Air Switching Valve (No. 2 ASV)(ASV1, 2) is a vacuum type.
The secondary air injection system pumps pressurized air to the exhaust port by the air pump through the ASV and No. 2 ASV. The ASV assists the No. 2 ASV. The No. 2 ASV also controls air supply.
The ECM sends signals to the AID, and then the AID operates the air pump and ASV. The pressure sensor detects pressure and exhaust pulsation in the system when the system operates and when it does not operate, and sends the data to the ECM.

Air injection (AIR) system does not operate (Air pump OFF and all ASVs OFF) 4Runner


DTC No.
DTC Detection Condition
Trouble Area
P0412
Both of the following conditions are met when engine is idling just after cold start
(1 trip detection logic):
  1. Air injection (AIR) system does not operate (Air pump OFF and all ASVs OFF)
  2. Air injection control driver (AID) diagnostic signal duty is 40 %
  1. Open in air switching valve drive circuit
  2. Short between air switching valve circuit and +B circuit
  3. Air injection control driver (AID)
  4. Air switching valve (ASV)
  5. ECM
P0412
Both of the following conditions are met when engine is idling just after cold start
(1 trip detection logic):
  1. Air injection (AIR) system operates (Air pump ON and all ASVs ON)
  2. Air injection control driver (AID) diagnostic signal duty is 40 %
  1. Short between air switching valve circuit and body ground
  2. AID
  3. ASV
  4. ECM

MONITOR DESCRIPTION

The Air Injection Control Driver (AID) detects an open or short in the circuit according to the voltage of the air pump terminal (VP) and electromagnetic air switching valve terminal (VV), and sends a signal as diagnostic information to the ECM.
The AID outputs the air switching valve terminal malfunction signal to the ECM if: 1) VV terminal voltage is low despite the AID receiving the command signal from the ECM to drive the air switching valve terminal or 2) VV terminal voltage is high despite the AID not receiving the command signal from the ECM.
The ECM stores the DTC based on the diagnostic signal from the AID and illuminates the MIL.

MONITOR STRATEGY


Related DTCs
P0412: Air switching valve circuit malfunction (Secondary air injection system)
Required sensors/components
Air injection control driver, Air switching valve
Frequency of operation
Continuous
Duration
3 seconds
MIL operation
Immediate
Sequence operation
None

TYPICAL ENABLING CONDITIONS


All:
The monitor will run whenever this DTC is not present
None

Case 1:
Air pump
Operating
Air switching valve
Operating
Battery voltage
8 V or more
Ignition switch
ON
Starter
OFF

Case 2:
Air pump
Not operating
Air switching valve
Not operating
Battery voltage
8 V or more
Ignition switch
ON
Starter
OFF

TYPICAL MALFUNCTION THRESHOLDS


Case 1, 2:
Diagnostic signal duty ratio from air injection driver
31 to 48 %

COMPONENT OPERATING RANGE


Diagnostic signal duty ratio from air injection control driver
70 to 90 % when secondary air injection system operating
and
0 % when secondary air injection system not operating

WIRING DIAGRAM


Start the engine and warm it up. 4Runner


INSPECTION PROCEDURE

HINT:
The diagnostic information output from Air Injection Control Driver (AID) can be confirmed by connecting an oscilloscope to the diagnostic information terminal of the AID. It narrows a trouble area search to read the waveform on the oscilloscope when performing the AIR system intrusive operation function provided in the SYSTEM CHECK.
  1. Start the engine and warm it up.
  2. Turn the ignition switch OFF.
  3. Connect the intelligent tester to the DLC3 with CAN VIM.
  4. Start the engine and turn the tester ON. 4Runner
    Connect an oscilloscope probe to the AIDI terminal of the ECM.
  5. Start the engine and turn the tester ON.
  6. Monitor the voltage output of the AID (duty ratio signal).Oscilloscope range ItemsContentsTerminalsCH1: AIDI - E1Equipment Settings5 V/DIV., 20 to 40 ms/DIV.ConditionsIdling 4Runner
    On the tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / SYSTEM CHECK / AIR INJ CHECK / MANUAL OPERATION / OPERATION 1 and 2.
    HINT:
    OPERATION 1: AP: OFF; EASV: CLOSE; ASV1: CLOSE; ASV2: CLOSE
    OPERATION 2: AP: ON; EASV: OPEN; ASV1: OPEN; ASV2: OPEN
  7. This AIR INJECTION CHECK only allows technicians to operate the AIR system for 5 seconds.Furthermore, the check can be performed 4 times a trip. If the test is repeated, intervals of at least 30 seconds are required between checks.While the AIR system operation using the intelligent tester is prohibited, the tester displays the prohibition (WAIT or ERROR). If ERROR (AI STATUS NG) is displayed on the tester, stop the engine for 10 minutes and then try again. 4Runner
    Monitor the voltage output of the AID (duty ratio signal).
    Oscilloscope range
    Items
    		Contents
    Terminals
    		CH1: AIDI - E1
    Equipment Settings
    		5 V/DIV., 20 to 40 ms/DIV.
    Conditions
    		Idling
NOTICE:
  1. This AIR INJECTION CHECK only allows technicians to operate the AIR system for 5 seconds.
    Furthermore, the check can be performed 4 times a trip. If the test is repeated, intervals of at least 30 seconds are required between checks.
    While the AIR system operation using the intelligent tester is prohibited, the tester displays the prohibition (WAIT or ERROR). If ERROR (AI STATUS NG) is displayed on the tester, stop the engine for 10 minutes and then try again.
  2. Performing the AIR INJ CHECK over and over again may cause damage in the secondary air injection system. If necessary, wait several minutes between tests to prevent overheating the system.
  3. When performing the AIR INJ CHECK operation after the battery cable has been reconnected, wait for 7 minutes with the ignition switch turned ON or the engine running.
  4. Turn the ignition switch OFF when the AIR INJ CHECK operation finishes.

AID Diagnostic Signal Waveform
ECM Command
DTC
(ECM Output)
Suspected Trouble Area
100 % Duty Ratio
See waveform 1
Any Air Injection (AIR) System operation
P1613
  1. Open in diagnostic signal circuit
  2. Air Injection Control Driver (AID)
  3. Open in AID +B circuit (AID power source)
  4. Short between +B circuit and diagnostic signal circuit
0 % Duty Ratio
See waveform 2
AIR System: ON
(Air pump ON, ASV ON)
P1613
  1. Open or short in air pump or Air Switching Valve (ASV) command signal circuit (ECM - AID)
  2. Open in AID ground circuit
  3. Short between diagnostic signal circuit and body ground
  4. AID
  5. ECM
AIR System: OFF
(Air pump OFF, ASV OFF)
-
  1. Normal
20 % Duty Ratio
See waveform 3
Air Pump: ON
P0418
  1. Short between air pump drive circuit and body ground
  2. Harness & connector (AID - Pump)
  3. Air Pump
  4. AID
  5. ECM
Air Pump: OFF
P0418
  1. Open in air pump drive circuit (AID - Pump), or short between air pump drive circuit and +B
  2. Harness & connector (AID - Pump)
  3. Air Pump
  4. AID
  5. ECM
40 % Duty Ratio
See waveform 4
ASV: ON
P0412
  1. Short between ASV drive circuit and body ground
  2. Harness & connector (AID - ASV)
  3. ASV
  4. AID
  5. ECM
ASV: OFF
P0412
  1. Open in ASV drive circuit (AID - ASV), or short between ASV drive circuit and +B
  2. Harness & connector (AID - ASV)
  3. AID
  4. ASV
  5. ECM
80 % Duty Ratio
See waveform 5
AIR System: OFF
(Air pump OFF, ASV OFF)
P1613
  1. AID
  2. ECM
AIR System: ON
(Air pump ON, ASV ON)
-
  1. Normal
Excluding Above
(excluding 0, 20, 40, 80, 100 % duty)
-
P1613
  1. AID
  2. Open in AID ground circuit

Waveform 1
100 % Duty Ratio 4Runner
  1. 100 % Duty Ratio

Waveform 2
0 % Duty Ratio 4Runner
  1. 0 % Duty Ratio

Waveform 3
20 % Duty Ratio 4Runner
  1. 20 % Duty Ratio

Waveform 4
40 % Duty Ratio 4Runner
  1. 40 % Duty Ratio

Waveform 5
80 % Duty Ratio 4Runner
  1. 80 % Duty Ratio
HINT:
  1. Using the AIR INJ CHECK operation of the SYSTEM CHECK provided in the intelligent tester function, conditions for air fuel ratio and pressure in the secondary air injection system passage can be checked while the secondary air injection system is operating. It helps technicians to troubleshoot the system when it is malfunctioning.
  2. Read freeze frame data using the intelligent tester. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. When troubleshooting, freeze frame data can be helpful in determining whether the vehicle was running or stopped, whether the engine was warmed up or not, whether the air/fuel ratio was lean or rich, as well as other data recorded at the time of a malfunction.
1.INSPECT AIR SWITCHING VALVE
  1. Remove the intake manifold (Click here). 4Runner

  2. Remove the intake manifold (Click here).

  1. Disconnect the A47 Air Switching Valve (ASV) connector.

  1. Measure the resistance of the ASV.

    Standard resistance:
    Tester Connection
    		Specified Condition
    1 - 2
    		4.5 to 5.5 Ω

  1. Reconnect the ASV connector.



NGnext
REPLACE AIR SWITCHING VALVE
OK
next down

2.CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - BODY GROUND)
  1. Remove the intake manifold (Click here). 4Runner

  2. Remove the intake manifold (Click here).

  1. Disconnect the A47 ASV connector.

  1. Check the resistance between the wire harness side connector and body ground.

    Standard resistance:
    Tester Connection
    		Specified Condition
    A47-2 - Body ground
    		Below 1 Ω

  1. Reconnect the ASV connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
next down

3.CHECK HARNESS AND CONNECTOR (AIR SWITCHING VALVE - AIR INJECTION CONTROL DRIVER)
  1. Remove the intake manifold (Click here). 4Runner

  2. Remove the intake manifold (Click here).

  1. Disconnect the A44 air injection driver connector.

  1. Disconnect the A47 air switching valve connector.

  1. Measure the resistance between the wire harness side connectors.

    Standard resistance:
    Tester Connection
    		Specified Condition
    VV (A44-6) - A47-1
    		Below 1 Ω
    VV (A44-6) or A47-1 - Body ground
    		10 kΩ higher

  1. Reconnect the air injection driver connector.

  1. Reconnect the ASV connector.



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
next down
REPLACE AIR INJECTION CONTROL DRIVER