Inspection Procedure

HINT:

Hand-held tester only:

Narrowing down the trouble area is possible by performing "A/F CONTROL" ACTIVE TEST (heated oxygen sensor or other trouble areas can be distinguished).

Perform the ACTIVE TEST's A/F CONTROL operation.

HINT:

"A/F CONTROL" is the ACTIVE TEST which changes the injection volume to-12.5 % or +25 %.

Connect the hand-held tester to the DLC3 on the vehicle.
Turn the ignition switch ON.
Warm up the engine by running the engine speed at 2,500 rpm for approximately 90 seconds.
Select the item "DIAGNOSIS/ENHANCED OBD II/ACTIVE TEST/A/F CONTROL".
Perform "A/F CONTROL" with the engine in an idle condition (press the right or left button).

RESULT:

Heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 % --> rich output: More than 0.5 V
-12.5 % --> lean output: Less than 0.4 V

NOTE: There is a delay of few seconds in the sensor 1 (front sensor) output, and there is about 20 seconds delay at maximum in the sensor 2 (rear sensor).

Fig 1: Active Test Result Table

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

To display the graph, enter the following menus: ACTIVE TEST/A/F CONTROL/USER DATA. Then select O2S B1S1 and O2S B1S2 by pressing YES. Finally, push ENTER and F4.

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, as well as other data from the time when a malfunction occurred.

Are there any other codes (besides DTC P0136) being output?

PREPARATION:

Connect the hand-held tester or the OBD II scan tool to the DLC3.
Turn the ignition switch ON and push the hand-held tester or the OBD II scan tool main switch ON.
When using the hand-held tester, enter the following menus: DIAGNOSIS/ENHANCED OBD II/DTC INFO/CURRENT CODES.

CHECK:

Read the DTCs using the hand-held tester or the OBD II scan tool.

RESULT:

DTC OUTPUT DISPLAY

Display (DTC output)	Proceed to
P0136	A
P0136 and other DTCs	B

HINT:

If any other codes besides P0136 are output, perform the troubleshooting for those DTCs first.

B : Go to relevant DTC chart (See DIAGNOSTIC TROUBLE CODE CHART ).
A : Go To Next Step

Check output voltage of oxygen sensor.
PREPARATION:
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Start the engine and push the hand-held tester or the OBD II scan tool main switch ON.
3. When using hand-held tester, enter the following menus: DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/O2S B1S1.
4. After warming up the engine, run the engine at 2,500 rpm for 3 minutes.
CHECK:

Read the output voltage of the heated oxygen sensor (sensor 2) when the engine rpm is suddenly increased.

HINT:

Quickly accelerate the engine to 4,000 rpm 3 times by using the accelerator pedal.

OK:
1. The output voltage of heated oxygen sensor (sensor 2): Alternates from 0.4 V or less to 0.5 V or more.
Fig 2: Output Voltage Display
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK : Go to step 6 .
2. NG : Go To Next Step.
Inspect resistance of heated oxygen sensor heater.
PREPARATION:

Disconnect the heated oxygen sensor connector.

CHECK:

Measure the resistance between the terminals HT and +B of the heated oxygen sensor.
1. Resistance:
2. Bank 1, 2 Sensor 1: 11 to 16 Ω (20°C (68°F))
Fig 3: Locating HT & +B terminals Of Heated Oxygen Sensor
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Replace heated oxygen sensor.
2. OK : Go To Next Step

Inspect EFI MAIN relay.

PREPARATION:

Remove the EFI MAIN relay from the engine room R/B.

CHECK:

Measure the resistance of the switch.

OK:

RESISTANCE MEASURING

Tester Connection	Specified Condition
1-2	Below 1 Ω
3-5	10 kΩor higher
3-5	Below 1 Ω (Apply battery voltage to terminals 1 and 2)

Fig 4: Measuring Resistance Of Switch

NG : Replace EFI MAIN relay.
OK : Go To Next Step

Check for open and short in harness and connector between ECM and oxygen sensor (See PROCEDURE ).

Fig 5: Bank 1 Sensor 1 System Drawing
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Repair or replace harness and connector.
2. OK : Replace heated oxygen sensor.
Perform confirmation driving pattern.
HINT:

Clear all DTCs prior to performing the confirmation driving pattern.
1. GO : Go To Next Step
Is there DTC P0136 being output again?
1. NO : Check for intermittent problems (See PRE-CHECK ).
2. YES : Replace heated oxygen sensor.