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 0.55 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, and other data from the time the malfunction occurred.
A high heated oxygen sensor (sensor 1) voltage (0.5 V or more) could be caused by a rich air fuel mixture. Check for conditions that would cause the engine to have a rich air-fuel mixture.
A low heated oxygen sensor (sensor 1) voltage (0.4 V or less) could be caused by a lean air fuel mixture. Check for conditions that would cause the engine to have a lean air-fuel mixture.

Are there any other codes (besides DTC P0134 or P0154) 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 OUT PUT DISPLAY

Display (DTC output)	Proceed to
P0134 and/or P0154	A
P0134 or P0154 and other DTCs	B

HINT:

If any other codes besides P0134 and/or P0154 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

Connect hand-held tester or OBD II scan tool and read value for voltage output of heated oxygen sensor.
PREPARATION:
1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
2. Turn the ignition switch ON and push the hand-held tester or the OBD II scan tool main switch ON.
3. When using the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II/DATA LIST / ALL / O2S B1S1 or B2 S1.
4. Warm up the engine to the normal operating engine coolant temperature above 75°C (169°F).
CHECK:

Read the output voltage of the heated oxygen sensor when the engine speed is suddenly increased.

HINT:

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

OK:
1. Heated oxygen sensor outputs a RICH signal (0.45 V or more) at least once.
1. OK : Go to step 12 .
2. NG : Go To Next Step.
Check connection of PCV piping.
1. NG : Repair or replace PCV piping.
2. OK : 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 2: 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 relay.

OK:

RESISTANCE MEASURING

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

Fig 3: Measuring Relay Resistance

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

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

Fig 4: Bank-1 Sensor-1 System Drawing
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG : Repair or replace harness and connector.
2. OK : Go To Next Step
Check whether misfire is occurred or not by monitoring DTC and data list.
1. NG : Perform troubleshooting for misfire (See page ##DI- 58).
2. OK : Go To Next Step
Check air induction system (See PRECAUTION ).
CHECK:

Check the air induction system for vacuum leaks.
1. NG : Repair or replace induction system.
2. OK : Go To Next Step
Check fuel pressure (See ON-VEHICLE INSPECTION ).
CHECK:

Check the fuel pressure (high or low pressure).
1. NG : Check and repair fuel pump, fuel pipe line and filter (See ON-VEHICLE INSPECTION ).
2. OK : Go To Next Step
Check injector injection (See INSPECTION ).
1. NG : Replace injector.
2. OK : Go To Next Step
Check gas leakage on exhaust system.
1. NG : Repair or replace exhaust gas leakage point.
2. OK : Replace heated oxygen sensor.
Perform confirmation driving pattern (See READINESS MONITOR DRIVE PATTERN ).
HINT:

Clear all DTCs prior to performing the confirmation pattern.
1. GO : Go To Next Step
Is there DTC P0134 or P0154 being output again?
1. YES : Replace ECM (See ENGINE CONTROL MODULE (ECM) ).
2. NO : Go To Next Step
Did vehicle run out of fuel in the past?
1. NO : Check for intermittent problems.
2. YES : DTC P0134 and P0154 are caused by running out of fuel.