Brand:

Toyota

Model Name:

4Runner GRN210 215 UZN210 215

Manual:

Repair Manual

Section:

1Gr-Fe Engine Control System

Title:

Sfi System

  1. Description

  2. Monitor description

  3. Confirmation driving pattern

  4. Monitor strategy

  5. Typical enabling conditions

  6. Typical malfunction thresholds

  7. Wiring diagram

  8. Inspection procedure

  9. Check any other dtcs output (in addition to dtc p2a00 and/or p2a03)

  10. Inspect air fuel ratio sensor (heater resistance)

  11. Check harness and connector (a/f sensor - ecm)

  12. Perform confirmation driving pattern

  13. Check whether dtc output recurs (dtc p2a00 and/or p2a03)

  14. Replace air fuel ratio sensor

  15. Perform confirmation driving pattern

  16. Check whether dtc output recurs (dtc p2a00 and/or p2a03)

DTC P2A00 A/F Sensor Circuit Slow Response (Bank 1 Sensor 1)

DTC P2A03 A/F Sensor Circuit Slow Response (Bank 2 Sensor 1)

HINT:
  1. DTC P2A00 means malfunctions related to the bank 1 A/F sensor.
  2. DTC P2A03 means malfunctions related to the bank 2 A/F sensor.
  3. Bank 1 refers to the bank that includes cylinder No. 1.
  4. Bank 2 refers to the bank that includes cylinder No. 2.
  5. Sensor 1 refers to the sensor mounted of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

DESCRIPTION

Refer to DTC P2195 (Click here).

DTC No.
DTC Detection Conditions
Trouble Areas
P2A00
P2A03
Calculated value for air-fuel ratio (A/F) sensor response rate deterioration level is less than threshold
  1. Open or short in A/F sensor circuit
  2. A/F sensor
  3. ECM

MONITOR DESCRIPTION

After engine is warmed up, the ECM performs air-fuel ratio feedback control to regulate the air-fuel ratio at stoichiometric ratio. In addition, this vehicle performs Active A/F Ratio Control for approximately 10 seconds after preconditions met in order to measure the A/F sensor response rate. During active air-fuel ratio control, the ECM forcibly increases and decreases the injection volume for certain amount based on learned stoichiometric air-fuel ratio during usual air-fuel feedback control, and measures the A/F sensor response rate. The ECM calculates the signal from the A/F sensor while performing the active A/F ratio control and interprets the calculated value as an test value for A/F sensor response rate deterioration level.
If the test value for A/F sensor response rate deterioration level is less than threshold, ECM interprets this as a malfunction, and sets the DTC.

Connect the intelligent tester to the DLC3 (Procedure "A"). 4Runner


CONFIRMATION DRIVING PATTERN

HINT:
Performing this confirmation pattern will activate the A/F sensor response monitor.

Connect the intelligent tester to the DLC3 (Procedure "A"). 4Runner

  1. Turn the ignition switch on (Procedure "B"). 4Runner
    Connect the intelligent tester to the DLC3 (Procedure "A").
  2. Turn the ignition switch on (Procedure "B").
  3. Turn the tester on (Procedure "C").
  4. Clear DTCs (Procedure "D").
  5. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / MONITOR INFO / MONITOR RESULT (Procedure "E").
  6. Check that AFS B1 is INCOMPL (Procedure "F").
  7. Start the engine and warm it up (Procedure "G").
  8. Drive the vehicle at between 25 mph and 75 mph (40 km/h and 120 km/h) for 3 minutes. However, the vehicle should be driven at a constant speed (Procedure "H").
  9. Check the monitor result values on the intelligent tester by selecting the following menu items: DIAGNOSIS / ENHANCED OBD II / MONITOR INFO / TEST RESULT (Procedure "I").
    HINT:
    The test values changes after monitor completed.
  10. If the values indicated on the tester does not change, perform READINESS MONITOR DRIVE PATTERN for the A/F sensor and the heated oxygen sensor (Click here) (Procedure "J").
    HINT:
    Completion of all A/F sensor monitors are required to change the value in TEST RESULT.
  11. Note the value of the Monitor Result (Procedure "K").
  12. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / PENDING CODES (Procedure "L").
  13. Check if any DTCs (any pending DTCs) are set (Procedure "M").

MONITOR STRATEGY


Related DTCs
P2A00: A/F sensor (Bank 1) slow response
P2A03: A/F sensor (Bank 2) slow response
Required Sensors / Components (Main)
A/F sensor
Required Sensors / Components (Related)
Vehicle speed sensor, Crankshaft position sensor
Frequency of Operation
Once per driving cycle
Duration
10 to 15 seconds
MIL Operation
2 driving cycles
Sequence of Operation
None

TYPICAL ENABLING CONDITIONS


The monitor will run whenever these DTCs are not present
P0031, P0032, P0051, P0052 (A/F Sensor heater Sensor 1), P0100, P0101, P0102, P0103 (MAF Sensor), P0110, P0112, P0113 (IAT Sensor), P0115, P0116, P0117, P0118 (ECT Sensor), P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135 (TP Sensor), P0125 (Insufficient ECT for Closed Loop), P0171, P0172 (Fuel System), P0300, P0301, P0302, P0303, P0304, P0305, P0306 (Misfire), P0335 (CKP Sensor), P0340 (CMP sensor), P0450, P0451, P0452, P0453, P0455, P0456 (EVAP System), P0500 (VSS), P2196, P2198 (A/F Sensor (Rationality))
Active A/F control
Performing
Active A/F control is performed when the following conditions are met
-
Battery voltage
11 V or more
Engine coolant temperature
75°C (167°F) or more
Idle
OFF
Engine RPM
Less than 4,000 rpm
A/F sensor status
Activated
Fuel cut
OFF
Engine load
10 to 70%
Shift position
2 or more
Catalyst monitor
Not yet
Intake air amount
2.5 to 8.2 g/s

TYPICAL MALFUNCTION THRESHOLDS


Response rate deterioration level
Less than 0.2 V

WIRING DIAGRAM

Refer to DTC P2195 (Click here).

INSPECTION PROCEDURE

HINT:
Malfunctioning areas can be identified by performing the A/F CONTROL function provided in the ACTIVE TEST. The A/F CONTROL function can help to determine whether the Air-Fuel Ratio (A/F) sensor, Heated Oxygen (HO2) sensor and other potential trouble areas are malfunctioning.
  1. The following instructions describe how to conduct the A/F CONTROL operation using an intelligent tester.
    1. Connect the intelligent tester to the DLC3.
    2. Start the engine and turn the tester on.
    3. Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
    4. Select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
    5. Perform the A/F CONTROL operation with the engine in an idling condition (press the RIGHT or LEFT button to change the fuel injection volume).
    6. Monitor the voltage outputs of the A/F and HO2 sensors (AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2) displayed on the tester.
      HINT:
      1. The A/F CONTROL operation lowers the fuel injection volume by 12.5% or increases the injection volume by 25%.
      2. Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

      Standard voltage:

      Tester Display (Sensor)
      		Injection Volumes
      		Status
      		Voltages
      AFS B1S1 or AFS B2S1 (A/F)
      		+25%
      		Rich
      		Less than 3.0
      AFS B1S1 or AFS B2S1 (A/F)
      		-12.5%
      		Lean
      		More than 3.35
      O2S B1S2 or O2S B2S2 (HO2)
      		+25%
      		Rich
      		More than 0.55
      O2S B1S2 or O2S B2S2 (HO2)
      		-12.5%
      		Lean
      		Less than 0.4
      NOTICE:
      The Air-Fuel Ratio (A/F) sensor has an output delay of a few seconds and the Heated Oxygen (HO2) sensor has a maximum output delay of approximately 20 seconds.

      Case
      		A/F Sensor (Sensor 1)
      Output Voltage
      		HO2 Sensor (Sensor 2)
      Output Voltage
      		Main Suspected Trouble Area
      1
      		Injection Volume
      +25 %
      -12.5%
      		A/F sensor 4Runner
      		Injection Volume
      +25%
      -12.5%
      		A/F sensor 4Runner
      		-
      Output Voltage
      More than 3.35 V
      Less than 3.0 V
      		A/F sensor 4Runner
      		Output Voltage
      More than 0.55 V
      Less than 0.4 V
      		A/F sensor 4Runner
      2
      		Injection Volume
      +25%
      -12.5%
      		A/F sensor 4Runner
      		Injection Volume
      +25%
      -12.5%
      		A/F sensor 4Runner
      1. A/F sensor
      2. A/F sensor heater
      3. A/F sensor circuit
      Output Voltage
      Almost
      no reaction
      		HO2 sensor 4Runner
      		Output Voltage
      More than 0.55 V
      Less than 0.4 V
      		HO2 sensor 4Runner
      3
      		Injection Volume
      +25%
      -12.5%
      		HO2 sensor 4Runner
      		Injection Volume
      +25%
      -12.5%
      		HO2 sensor 4Runner
      1. HO2 sensor
      2. HO2 sensor heater
      3. HO2 sensor circuit
      Output Voltage
      More than 3.35 V
      Less than 3.0 V
      		Injector 4Runner
      		Output Voltage
      Almost
      no reaction
      		Injector 4Runner
      4
      		Injection volume
      +25%
      -12.5%
      		Injector 4Runner
      		Injection Volume
      +25%
      -12.5%
      		Injector 4Runner
      1. Injector
      2. Fuel pressure
      3. Gas leakage from exhaust system
        (Air-fuel ratio extremely lean or rich)
      Output Voltage
      Almost
      no reaction
      		Following the A/F CONTROL procedure enables technicians to check the graph the voltage outputs of both the A/F and HO2 sensors.To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2, and press the YES button and then the ENTER button followed by the F4 button.HINT: DTC P2A00 or P2A03 may be also set, when the air-fuel ratio is stuck rich or lean.A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.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. 4Runner
      		Output Voltage
      Almost
      no reaction
      		Following the A/F CONTROL procedure enables technicians to check the graph the voltage outputs of both the A/F and HO2 sensors.To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2, and press the YES button and then the ENTER button followed by the F4 button.HINT: DTC P2A00 or P2A03 may be also set, when the air-fuel ratio is stuck rich or lean.A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.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. 4Runner
    1. Following the A/F CONTROL procedure enables technicians to check the graph the voltage outputs of both the A/F and HO2 sensors.
    2. To display the graph, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL / USER DATA / AFS B1S1 and O2S B1S2 or AFS B2S1 and O2S B2S2, and press the YES button and then the ENTER button followed by the F4 button.
      HINT:
      1. DTC P2A00 or P2A03 may be also set, when the air-fuel ratio is stuck rich or lean.
      2. A low A/F sensor voltage could be caused by a rich air-fuel mixture. Check for conditions that would cause the engine to run rich.
      3. A high A/F sensor voltage could be caused by a lean air-fuel mixture. Check for conditions that would cause the engine to run lean.
      4. 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.CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P2A00 AND/OR P2A03)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch on.

  1. Turn the tester on.

  1. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

  1. Read DTCs.

    Result:

    Display (DTC Output)
    		Proceed to
    P2A00 and/or P2A03
    		A
    P2A00 and/or P2A03 and other DTCs
    		B
    HINT:
    If any DTCs other than P2A00 or P2A03 are output, troubleshoot those DTCs first.


Bnext
GO TO DTC CHART
A
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2.INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
  1. Disconnect the A12 or A13 A/F sensor connector. 4Runner

  2. Disconnect the A12 or A13 A/F sensor connector.

  1. Measure the resistance between the terminals of the A/ sensor connector.

    Standard resistance:
    Bank 1:
    Tester Connections
    		Specified Conditions
    HT (1) - +B (2)
    		1.8 to 3.4 Ω at 20°C (68°F)
    HT (1) - AF- (4)
    		10 kΩ or higher
    Bank 2:
    Tester Connections
    		Specified Conditions
    HT (1) - +B (2)
    		1.8 to 3.4 Ω at 20°C (68°F)
    HT (1) - AF- (4)
    		10 kΩ or higher

  1. Reconnect the A/F sensor connector.



NGnext
REPLACE AIR FUEL RATIO SENSOR
OK
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3.CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
  1. Disconnect the A12 or A13 A/F sensor connector. 4Runner

  2. Disconnect the A12 or A13 A/F sensor connector.

  1. Turn the ignition switch on.

  1. Measure the voltage between the +B terminal of the A/F sensor connector and body ground.

    Standard voltage:
    Tester Connections
    		Specified Conditions
    +B (A12-2) - Body ground
    		9 to 14 V
    +B (A13-2) - Body ground
    		9 to 14 V

  1. Turn the ignition switch off.

  1. Disconnect the B46 ECM connector.

  1. Measure the resistance between the terminals of the A/F sensor connector and ECM connector.

    Standard resistance (Check for open):
    Tester Connections
    		Specified Conditions
    HA1A (A12-1) - HA1A (E5-2)
    		Below 1 Ω
    A1A+ (A12-3) - A1A+ (E5-22)
    		Below 1 Ω
    A1A- (A12-4) - A1A- (E5-30)
    		Below 1 Ω
    HA2A (A13-1) - HA2A (E5-1)
    		Below 1 Ω
    A2A+ (A13-3) - A2A+ (E5-23)
    		Below 1 Ω
    A2A- (A13-4) - A2A- (E5-31)
    		Below 1 Ω
    Standard resistance (Check for short):
    Tester Connections
    		Specified Conditions
    HA1A (A12-1) or HA1A (E5-2) - Body ground
    		10 kΩ or higher
    A1A+ (A12-3) or A1A+ (E5-22) - Body ground
    		10 kΩ or higher
    A1A- (A12-4) or A1A- (E5-30) - Body ground
    		10 kΩ or higher
    HA2A (A13-1) or HA2A (E5-1) - Body ground
    		10 kΩ or higher
    A2A+ (A13-3) or A2A+ (E5-23) - Body ground
    		10 kΩ or higher
    A2A- (A13-4) or A2A- (E5-31) - Body ground
    		10 kΩ or higher

  1. Reconnect the ECM connector.

  1. Reconnect the A/F sensor connector.


    Read DTCs using the intelligent tester. 4Runner



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
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4.PERFORM CONFIRMATION DRIVING PATTERN

NEXT
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5.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

  1. Read DTCs using the intelligent tester.

  1. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

    Result:

    Display (DTC Output)
    		Proceed to
    P2A00 and/or P2A03
    		A
    No output
    		B


Bnext
CHECK FOR INTERMITTENT PROBLEMS
A
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6.REPLACE AIR FUEL RATIO SENSOR

NEXT
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7.PERFORM CONFIRMATION DRIVING PATTERN

NEXT
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8.CHECK WHETHER DTC OUTPUT RECURS (DTC P2A00 AND/OR P2A03)

  1. Read DTCs using the intelligent tester.

  1. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

    Result:

    Display (DTC Output)
    		Proceed to
    No output
    		A
    P2A00 and/or P2A03
    		B


Bnext
CHECK EXTREMELY RICH OR LEAN ACTUAL AIR FUEL RATIO (REFER TO DTC P0171 PROCEDURE)
A
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END