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 And Heated Oxygen Sensor 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.

CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0136 AND/OR P0156)
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 DTCs.
  Result:
  
  Fig 2: DTC Output Result Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
HINT: If any other codes besides P0136 and/or P0156 are output, perform troubleshooting for those DTCs first.

B: GO TO RELEVANT DTC CHART (See DIAGNOSTIC TROUBLE CODE CHART )

A: GO TO NEXT STEP.
READ VALUE OF HAND-HELD TESTER OR OBD II SCAN TOOL (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
1. After warming up the engine, run the engine at 2,500 RPM for 3 minutes.
2. Read the output voltage of the heated oxygen sensor when the engine RPM is suddenly increased.
HINT: Quickly accelerate the engine to 4,000 RPM 3 times by using the accelerator pedal.

Heated oxygen sensor output voltage: Alternates 0.4 V or less and 0.5 V or more.

OK: Go to step

NG: GO TO NEXT STEP.
INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)
1. Disconnect the H9 or H10 heated oxygen sensor connector.
2. Measure the resistance between the terminals of the heated oxygen sensor connector.
  Standard (Bank 1, 2 sensor 2):
  
  Fig 3: Heated Oxygen Sensor Terminals Specified Condition Chart (Bank 1, 2 Sensor 2)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Reconnect the heated oxygen sensor connector.
  
  Fig 4: Identifying Heated Oxygen Sensor Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE HEATED OXYGEN SENSOR

OK: GO TO NEXT STEP.
INSPECT EFI RELAY
1. Remove the EFI relay from the engine room J/B.
2. Check for continuity in the EFI relay.
  Standard:
  
  Fig 5: EFI Relay Connector Terminals Continuity Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Reinstall the EFI relay.
  
  Fig 6: Checking Continuity Between EFI Relay Connector Terminals
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPLACE EFI RELAY

OK: GO TO NEXT STEP.
CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)
1. Disconnect the H9 or H10 heated oxygen sensor connector.
2. Disconnect the E9 ECM connector.
3. Check the resistance between the wire harness side connectors.
  Standard (Check for open):
  
  Fig 7: Heated Oxygen Sensor And ECM Terminals Specified Condition Chart (Check For Open)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Standard (Check for short):
  
  Fig 8: Heated Oxygen Sensor And ECM Terminals Specified Condition Chart (Check For Short)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. Reconnect the heated oxygen sensor connector.
5. Reconnect the ECM connector.
  
  Fig 9: Identifying Heated Oxygen Sensor Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 10: Disconnecting E9 ECM Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 11: Heated Oxygen Sensor Connector Reference Chart (Bank 1 Sensor 2 System)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: GO TO NEXT STEP.

REPLACE HEATED OXYGEN SENSOR
PERFORM CONFIRMATION DRIVING PATTERN
HINT: Clear all DTCs prior to performing the confirmation driving pattern.

GO: GO TO NEXT STEP.
READ OUTPUT DTC (SEE IF DTC P0136 AND/OR P0156 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 12: DTC Output Result Table
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
B: REPLACE HEATED OXYGEN SENSOR

A: GO TO NEXT STEP.

CHECK FOR INTERMITTENT PROBLEMS (See CHECK FOR INTERMITTENT PROBLEMS )