Inspection Procedure

WARNING: This page is about a different car, the 2004 Lexus ES 330. However, it is still accessible from the selected car via links, so may be relevant.

HINT: Hand-held tester only:

It is possible the malfunctioning area can be found using the ACTIVE TEST A/F CONTROL operation. The A/F CONTROL operation can determine if the A/F sensor, heated oxygen sensor or other potential trouble areas are malfunctioning or not.

Perform the ACTIVE TEST A/F CONTROL operation.
HINT: The A/F CONTROL operation lowers the injection volume 12.5% or increases the injection volume 25%.
1. Connect the hand-held tester to the DLC3 on the vehicle.
2. Turn the ignition switch to ON.
3. Warm up the engine by running the engine at 2,500 RPM for approximately 90 seconds.
4. Select the item: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST / A/F CONTROL.
5. Perform the A/F CONTROL operation with the engine in an idle condition (press the right or left button).
  Result:
  
  A/F sensor reacts in accordance with increase and decrease of injection volume:
  
  +25% --> rich output: Less than 3.0 V
  
  -12.5% --> lean output: More than 3.35 V
  
  Heated oxygen sensor reacts in accordance with increase and decrease of injection volume:
  
  +25% --> rich output: More than 0.55 V
  
  -12.5% --> lean output: Less than 0.4 V

NOTE: The A/F sensor output has a few seconds of delay and the heated oxygen sensor output has about 20 seconds of delay at maximum.

Fig 1: A/F Sensor (Sensor 1) And Heated Oxygen Sensor (Sensor 2) Output Voltage Chart

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The following A/F CONTROL procedure enables the technician to check and graph the voltage outputs of both the A/F sensor and the heated oxygen sensor.

To display the graph, enter ACTIVE TEST/ A/F CONTROL/USER DATA, then select "AFS B1S1 and O2S B1S2" or "AFS B2S1 and O2S B2S2" by pressing the "YES" button followed by the "ENTER" button and then the "F4" button.

HINT:

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, 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.
A high A/F sensor voltage could be caused by a RICH air-fuel mixture. Check the conditions that would cause the engine to run with a RICH air-fuel mixture.
A low A/F sensor voltage could be caused by a LEAN air-fuel mixture. Check the conditions that would cause the engine to run with a LEAN air-fuel mixture.

CHECK AIR INDUCTION SYSTEM
1. Check for vacuum leaks in the air induction system.
NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK: GO TO NEXT STEP.
CHECK CONNECTION OF PCV HOSE
NG: REPAIR OR REPLACE HOSE

OK: GO TO NEXT STEP.
INSPECT FUEL INJECTOR ASSY (INJECTION AND VOLUME) (See INSPECTION )
NG: REPLACE FUEL INJECTOR ASSY (See FUEL INJECTOR ASSY (3MZ-FE) )

OK: GO TO NEXT STEP.
INSPECT MASS AIR FLOW SENSOR
1. Remove the mass air flow sensor.
2. Inspect output voltage.
  1. Apply battery voltage across terminals +B and E2G.
  2. Connect the positive (+) tester prove to terminal VG, and negative (-) tester prove to terminal E2G.
  3. Blow air into the mass air flow sensor, and check that the voltage fluctuates.
3. Inspect resistance.
  1. Measure the resistance between the terminals of the intake air temperature sensor.
    Standard:
    
    Fig 2: Mass Air Flow Sensor Terminals Specified Condition Chart
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reinstall the mass air flow sensor.
  
  Fig 3: Mass Air Flow Sensor Terminals Resistance Graph
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE MASS AIR FLOW SENSOR

OK: GO TO NEXT STEP.
INSPECT ENGINE COOLANT TEMPERATURE SENSOR (RESISTANCE)
1. Remove the engine coolant temperature sensor.
2. Measure the resistance between the terminals of the engine coolant temperature sensor.
  Standard:
  
  Fig 4: Engine Coolant Temperature Sensor Terminals Specified Condition Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  NOTE: When checking the engine coolant temperature sensor in water, be careful not to allow water to contact the terminals. After checking, dry the sensor.
  
  HINT: Alternate procedure: Connect an ohmmeter to the installed engine coolant temperature sensor and read the resistance. Use an infrared thermometer to measure the engine temperature in the immediate vicinity of the sensor. Compare these values to the resistance/temperature graph. Change the engine temperature (warm up or allow to cool down) and repeat the test.
3. Reinstall the engine coolant temperature sensor.
  
  Fig 5: Measure Resistance Between Terminals Of Engine Coolant Temperature Sensor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE ENGINE COOLANT TEMPERATURE SENSOR

OK: GO TO NEXT STEP.
CHECK FOR SPARK AND IGNITION (See IGNITION SYSTEM (3MZ-FE) )
NG: REPAIR OR REPLACE

OK: GO TO NEXT STEP.
CHECK FUEL PRESSURE (See ON-VEHICLE INSPECTION )
1. Check the fuel pressure (high or low pressure).
NG: REPAIR FUEL SYSTEM

OK: GO TO NEXT STEP.
CHECK FOR EXHAUST GAS LEAKAGE
NG: REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT (See EXHAUST )

OK: GO TO NEXT STEP.
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (OUTPUT VOLTAGE OF AIR FUEL RATIO SENSOR (BANK 1, 2 SENSOR 1))
1. Connect the hand-held tester or the OBD II scan tool to the DLC 3.
2. Warm up the A/F sensors (bank 1, 2 sensor 1) by running the engine at 2,500 RPM for approximately 90 seconds.
3. Read A/F sensor voltage output on the OBD II scan tool or the hand-held tester.
4. Hand-held tester only:
  On the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / SNAPSHOT / MANUAL SNAPSHOT / USER DATA. Read the values.
5. Select the item "AFS B1 S1 or AFS B2 S1/ENGINE SPD" and press YES.
6. Monitor the A/F sensor voltage carefully.
7. Check the A/F sensor voltage output under the following conditions:
  1. Allow the engine to idle for 30 seconds.
  2. Running the engine at approximately 2,500 RPM (where engine RPM is not suddenly changed).
  3. Raise the engine speed to 4,000 RPM and quickly release the accelerator pedal so that the throttle is fully closed.
    Standard:
    
    Condition (1) and (2)
    
    Voltage change of 3.3 V (0.66 V) (*) (between approximately 3.1 to 3.5 V) as shown in the illustration.
    
    Condition (3)
    
    A/F sensor voltage increases to 3.8 V (0.76 V) (*) or more when fuel is cut during engine deceleration, as shown in the illustration.
    
    (*) Voltage when using the OBD II scan tool.
    
    Fig 6: A/F Sensor Output Voltage Chart (Normal/Malfunction Condition)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT:
- Whenever the output voltage of the A/F sensor remains at approximately 3.3 V (0.660 V) (*) (see "Malfunction Condition" graphic) under any condition as well as the above conditions, the A/F sensor may have an open-circuit. (This will happen also when the A/F sensor heater has an open-circuit.)
- Whenever the output voltage of the A/F sensor remains at a certain value of approximately 3.8 V (0.76 V) (*) or more, or 2.8 V (0.56 V) (*) or less (see "Malfunction Condition" graphic) under any condition as well as the above conditions, the A/F sensor may have a short-circuit.
- The ECM will stop fuel injection (fuel cut) during engine deceleration. This will cause a LEAN condition and should result in a momentary increase in A/F sensor voltage output.
- The ECM must establish a closed throttle position learned value to perform fuel cut. If the battery terminal has been disconnected, the vehicle must be driven over 10 mph (16km/h) to allow the ECM to learn the closed throttle position.
- When the vehicle is driven:
  The output voltage of the A/F sensor may be below 2.8 V (0.76 V) (*) during fuel enrichment. For the vehicle, this translates to a sudden increase in speed with the accelerator pedal fully depressed when trying to overtake another vehicle. The A/F sensor is functioning normally.
- The A/F sensor is a current output element, and therefore the current is converted into voltage inside the ECM. If measuring voltage at connectors of A/F sensor or ECM, you will observe a constant voltage.
Voltage when using the OBD II scan tool.

OK: Go to step 14

NG: GO TO NEXT STEP.
INSPECT AIR FUEL RATIO SENSOR (HEATER RESISTANCE)
1. Disconnect the A10 or A11 A/F sensor connector.
2. Measure the resistance between the terminals of the A/F sensor.
  Resistance:
  
  Fig 7: Air Fuel Ratio Sensor Terminals Resistance Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Reconnect the A/F sensor connector.
  
  Fig 8: Identifying Air Fuel Ratio Sensor Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE AIR FUEL RATIO SENSOR

OK: GO TO NEXT STEP.
INSPECT AIR FUEL RATIO SENSOR HEATER RELAY
1. Remove the A/F sensor heater relay from the engine room R/B.
2. Check for continuity in the A/F sensor heater relay.
  Standard:
  
  Fig 9: Air Fuel Ratio Sensor Heater Relay Terminals Continuity Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Reinstall the A/F sensor heater relay.
  
  Fig 10: Checking Continuity Between Air Fuel Ratio Sensor Heater Relay Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE AIR FUEL RATIO SENSOR HEATER RELAY

OK: GO TO NEXT STEP.
CHECK HARNESS AND CONNECTOR (A/F SENSOR - ECM)
1. Disconnect the A10 or A11 A/F sensor connector.
2. Disconnect the E9 ECM connector.
3. Check the resistance between the wire harness side connectors.
  Standard (Check for open):
  
  Fig 11: A/F Sensor And ECM Terminals Specified Condition Chart (Check For Open)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard (Check for short):
  
  Fig 12: A/F Sensor And ECM Terminals Specified Condition Chart (Check For Short)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the A/F sensor connector.
5. Reconnect the ECM connector.
  
  Fig 13: Identifying A/F Sensor Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 14: Disconnecting E9 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 15: A/F Sensor Connectors Reference Chart (Bank 1 Sensor 1 System Drawing)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO NEXT STEP.
REPLACE AIR FUEL RATIO SENSOR
GO: GO TO NEXT STEP.
PERFORM CONFIRMATION DRIVING PATTERN

Fig 16: Vehicle Speed Perform Confirmation Driving Pattern Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. Clear the DTCs.
  1. Disconnect the battery terminal or remove the EFI and ETCS fuses for 60 seconds or more.
2. Connect the hand-held tester to the DLC3.
3. Switch the hand-held tester from the normal mode to the check mode (see CHECK MODE PROCEDURE ).
4. Start the engine and warm it up with all the accessory switched OFF.
5. Drive the vehicle at 38 to 75 mph (60 to 120 km/h) and engine speed at 1,400 to 3,200 RPM for 3 to 5 minutes.
HINT: If a malfunction exists, the MIL will be illuminated during step (e).

NOTE: If the conditions in this test are not strictly followed, no malfunction will be defected. If you do not have a hand-held tester, turn the ignition switch OFF after performing steps (d) and (e), then perform step (e) again.

GO: GO TO NEXT STEP.
READ OUTPUT DTC (SEE IF DTC P0171, P0172, P0174 AND/OR P0175 ARE OUTPUT AGAIN)
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
3. Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
4. Read the DTCs.
  Result:
  
  Fig 17: DTC Output Result Table (1 Of 3)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
B: REPLACE ECM (See ECM (3MZ-FE) ) AND PERFORM CONFIRMATION DRIVING PATTERN (Refer to step 14)

A: GO TO NEXT STEP.
CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
NO: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )

YES: GO TO NEXT STEP.

DTC IS CAUSED BY RUNNING OUT OF FUEL (DTCS P0171, P0172, P0174 AND/OR P0175)
PERFORM CONFIRMATION DRIVING PATTERN
HINT: Clear all DTCs prior to performing the confirmation driving pattern (Refer to step 14).

GO: GO TO NEXT STEP.
READ OUTPUT DTC (SEE IF DTC P0171, P0172, P0174 AND/OR P0175 ARE OUTPUT AGAIN)
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
3. Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
4. Read the DTCs.
  Result:
  
  Fig 18: DTC Output Result Table (2 Of 3)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
B: Go to step 22

A: GO TO NEXT STEP.
REPLACE AIR FUEL RATIO SENSOR
GO: GO TO NEXT STEP.
PERFORM CONFIRMATION DRIVING PATTERN
HINT: Clear all DTCs prior to performing the confirmation driving pattern (Refer to step 14).

GO: GO TO NEXT STEP.
READ OUTPUT DTC (SEE IF DTC P0171, P0172, P0174 AND/OR P0175 ARE OUTPUT AGAIN)
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool ON.
3. Select the item: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
4. Read the DTCs.
  Result:
  
  Fig 19: DTC Output Result Table (3 Of 3)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
B: REPLACE ECM (See ECM (3MZ-FE) ) AND PERFORM CONFIRMATION DRIVING PATTERN (Refer to step 14)

A: GO TO NEXT STEP.
CONFIRM IF VEHICLE HAS RUN OUT OF FUEL IN PAST
NO: CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )

YES: GO TO NEXT STEP.

DTC IS CAUSED BY RUNNING OUT OF FUEL (DTCS P0171, P0172, P0174 AND/OR P0175)