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. Monitor strategy

  4. Typical enabling conditions

  5. Typical malfunction thresholds

  6. Wiring diagram

  7. Inspection procedure

  8. Inspect air fuel ratio sensor (heater resistance)

  9. Inspect air fuel ratio sensor heater relay

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

DTC P2238 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 1 Sensor 1)

DTC P2239 Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 1 Sensor 1)

DTC P2241 Oxygen (A/F) Sensor Pumping Current Circuit Low (Bank 2 Sensor 1)

DTC P2242 Oxygen (A/F) Sensor Pumping Current Circuit High (Bank 2 Sensor 1)

DTC P2252 Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 1 Sensor 1)

DTC P2253 Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 1 Sensor 1)

DTC P2255 Oxygen (A/F) Sensor Reference Ground Circuit Low (Bank 2 Sensor 1)

DTC P2256 Oxygen (A/F) Sensor Reference Ground Circuit High (Bank 2 Sensor 1)

HINT:
  1. Although the DTC titles say oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
  2. Sensor 1 refers to the sensor mounted in front 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
P2238
P2241
  1. Case 1:
    Condition (a) or (b) continues for 5.0 seconds or more (1 trip detection logic):
    (a) AF+ voltage is 0.5 V or less
    (b) (AF+) - (AF-) = 0.1 V or less
  2. Case 2:
    A/F sensor admittance: Less than 0.022 1/Ω (2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F sensor heater relay
  5. A/F sensor heater and relay circuits
  6. ECM
P2239
P2242
AF+ voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor
  3. A/F sensor heater
  4. A/F sensor heater relay
  5. A/F sensor heater and relay circuits
  6. ECM
P2252
P2255
AF- voltage is 0.5 V or less for 5.0 seconds or more (2 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F sensor heater relay
  5. A/F sensor heater and relay circuits
  6. ECM
P2253
P2256
AF- voltage is more than 4.5 V for 5.0 seconds or more (1 trip detection logic)
  1. Open or short in A/F sensor (bank 1, 2 sensor 1) circuit
  2. A/F sensor (bank 1, 2 sensor 1)
  3. A/F sensor heater
  4. A/F sensor heater relay
  5. A/F sensor heater and relay circuits
  6. ECM
HINT:
  1. DTC P2238, P2239, P2252 and P2253 means malfunction related to the bank 1 A/F sensor circuit.
  2. DTC P2241, P2242, P2255 and P2256 means malfunction related to the bank 2 A/F sensor circuit.
  3. Bank 1 refers to the bank that includes cylinder No. 1.
  4. Bank 2 refers to the bank that includes cylinder No. 2.

MONITOR DESCRIPTION

The Air-Fuel Ratio (A/F) sensor varies its output voltage in proportion to the air-fuel ratio. If the A/F sensor impedance (alternating current resistance) or voltage output deviates greatly from the standard range, the ECM determines that there is an open or short malfunction in the A/F sensor circuit.

MONITOR STRATEGY


Related DTCs
P2238: A/F sensor (Bank 1) open circuit between AF+ and AF-
P2238: A/F sensor (Bank 1) short circuit between AF+ and AF-
P2238: A/F sensor (Bank 1) short circuit between AF+ and GND
P2239: A/F sensor (Bank 1) short circuit between AF+ and +B
P2241: A/F sensor (Bank 2) open circuit between AF+ and AF-
P2241: A/F sensor (Bank 2) short circuit between AF+ and AF-
P2241: A/F sensor (Bank 2) short circuit between AF+ and GND
P2242: A/F sensor (Bank 2) short circuit between AF+ and +B
P2252: A/F sensor (Bank 1) short circuit between AF- and GND
P2253: A/F sensor (Bank 1) short circuit between AF- and +B
P2255: A/F sensor (Bank 2) short circuit between AF- and GND
P2256: A/F sensor (Bank 2) short circuit between AF- and +B
Required Sensors / Components (Main)
A/F sensor
Required Sensors / Components (Related)
ECT sensor, Crankshaft position sensor
Frequency of Operation
Once per driving cycle
Duration
10 seconds: A/F sensor open circuit between AF+ and AF-
5 seconds: Others
MIL Operation
2 driving cycles
Sequence of Operation
None

TYPICAL ENABLING CONDITIONS


All:
The monitor will run whenever these DTCs are not present
None

P2238 and P2241 (open circuit between AF+ and AF-):
AF+ terminal voltage
0.5 to 4.5 V
AF- terminal voltage
0.5 to 4.5 V
Difference between AF+ terminal and AF- terminal voltages
0.1 to 0.8 V
ECT
5°C (41°F) or more
Engine
Running
Fuel-cut
OFF
Time after A/F sensor heating
0% or more
A/F sensor heater duty ratio
20 seconds or more
Battery voltage
11 V or more
Ignition switch
ON
Time after ignition switch is OFF to ON
5 seconds or more

Others:
Battery voltage
11 V or more
Ignition switch
ON
Time after ignition switch is OFF to ON
5 seconds or more

TYPICAL MALFUNCTION THRESHOLDS


P2238, P2241 (Open circuit between AF+ and AF-):
A/F sensor admittance
Below 0.022 1/Ω

P2238, P2241 (Short circuit between AF+ and GND):
AF+ terminal voltage
0.5 V or less

P2238, P2241 (Short circuit between AF+ and AF-):
Difference between AF+ and AF- terminal voltages
0.1 V or less

P2239, P2242 (Short circuit between AF+ and +B):
AF+ terminal voltage
More than 4.5 V

P2252, P2255 (Short circuit between AF- and GND):
AF- terminal voltage
0.5 V or less

P2253, P2256 (Short circuit between AF- and +B):
AF- terminal voltage
More than 4.5 V

WIRING DIAGRAM

Refer to DTC P2195 (Click here).

INSPECTION PROCEDURE

HINT:
For use the intelligent tester only:
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 the 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 of 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: 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 of 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: 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 of 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. 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 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/F 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.



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REPLACE AIR FUEL RATIO SENSOR
OK
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2.INSPECT AIR FUEL RATIO SENSOR HEATER RELAY
  1. Remove the A/F sensor heater relay from the engine room R/B. 4Runner

  2. Remove the A/F sensor heater relay from the engine room R/B.

  1. Check the A/F sensor heater relay resistance.

    Standard resistance:
    Tester Connections
    		Specified Conditions
    3 - 5
    		10 kΩ or higher
    3 - 5
    		Below 1 Ω
    (when battery voltage applied to terminals 1 and 2)

  1. Reinstall the A/F sensor heater relay.



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REPLACE AIR FUEL RATIO SENSOR HEATER RELAY
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 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.


    Sfi System - P0328 4Runner



NGnext
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK
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REPLACE ECM