Inspection Procedure

WARNING: This page is about a different variant/trim than selected.

HINT:

Hand held 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 Heated Oxygen (HO2) sensors and other potential trouble areas are malfunctioning.

The following instructions describe how to conduct the A/F CONTROL operation using a hand-held tester.

Connect a hand-held tester to the DLC3.
Start the engine and turn the tester ON.
Warm up the engine at an engine speed of 2,500 rpm for approximately 90 seconds.
On the tester, select the following menu items: DIAGNOSIS/ENHANCED OBD II/ACTIVE TEST/A/F CONTROL.
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).
Monitor the voltage output of the HO2 sensors (O2S B1S1 and OS2 B1S2) displayed on the tester.

HINT:

The A/F CONTROL operation lowers the fuel injection volume by 12.5 % or increases the injection volume by 25 %.
Each sensor reacts in accordance with increases and decreases in the fuel injection volume.

Standard:

DISPLAY STATUS

Tester Display (Sensor)	Injection Volumes	Status	Voltages
O2S B1S1 (Front HO2 Sensor)	+25 %	Rich	More than 0.5
O2S B1S1 (Front HO2 Sensor)	-12.5 %	Lean	Less than 0.4
O2S B1S2 (Rear HO2 Sensor)	+25 %	Rich	More than 0.5
O2S B1S2 (Rear HO2 Sensor)	-12.5 %	Lean	Less than 0.4

NOTE: The front HO2 sensor has an output delay of a few seconds and the rear HO2 sensor has a maximum output delay of approximately 20 seconds.

Fig 1: Output Voltage Reference Chart

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Following the A/F CONTROL procedure enables technicians to check and graph the voltage outputs of both the front and rear 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 B1S2 and OS2 B1B2, and press the YES button and then the ENTER button followed by the F4 button.

NOTE: If the vehicle is short of fuel, the air-fuel ratio becomes lean and HO2 sensor DTCs are recorded, and the ECM illuminates the MIL.

HINT:

If other DTCs relating to different systems that have terminal E2 as the ground terminal are output simultaneously, terminal E2 may have an open circuit.
Read freeze frame data using a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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 HO2 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 run rich.
A low HO2 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 run lean.

CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0134)

Connect a hand-held tester or OBD II scan tool to the DLC3.
Turn the ignition switch to ON.
Turn the tester or scan tool ON.
On the tester, select the following menu items: DIAGNOSIS/ENHANCED OBD II/DTC INFO/CURRENT CODES.
Read DTCs.
If using an OBD II scan tool, refer to the instruction manual.

Result:

RESULT REFERENCE

Display (DTC Output)	Proceed To
P0134	A
P0134 and other DTCs	B

HINT:

If any DTCs other than P0134 are output, troubleshoot those DTCs first.

B: GO TO DIAGNOSTIC TROUBLE CODE CHART )

A: Go to next step.

READ VALUE USING HAND HELD TESTER OR OBD II SCAN TOOL (OUTPUT VOLTAGE OF HEATED OXYGEN SENSOR)
1. Connect the hand-held tester or OBD II scan tool to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the tester or scan tool ON.
4. Start the engine.
5. On the tester, select the following menu items: DIAGNOSIS/ENHANCED OBD II/DATA LIST/ALL/O2S B1S1 and ENGINE SPD.
6. Warm up the engine until the engine coolant temperature reaches more than 75°C (169°F).
7. Rev the engine up to 4,000 rpm, 3 times using the accelerator pedal.
8. Read the output voltage of the front HO2 sensor displayed on the tester, when the engine speed is suddenly increased.
9. If using an OBD II scan tool, refer to the instruction manual.
Standard: HO2 sensor voltage output indicates 0.45 V or more (rich signal) at least once.

OK: Go to step 14

NG: Go to next step.
CHECK PCV HOSE CONNECTIONS
OK: PCV hose is connected correctly and is not damaged.

NG: REPAIR OR REPLACE PCV HOSE

OK: Go to next step.

INSPECT HEATED OXYGEN SENSOR (HEATER RESISTANCE)

Disconnect the H5 HO2 sensor connector.

Measure the resistance between the terminals of the HO2 sensor connector.

Standard:

TESTER CONNECTIONS SPECIFIED CONDITIONS (1 OF 3)

Tester Connections	Specified Conditions
HT (1) - +B (2)	Between 5 Ω and 10 Ω at 20°C (68°F)
HT (1) - E1 (4)	10 kΩ or higher

Reconnect the HO2 sensor connector.

Fig 2: Identifying H5 HO2 Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE HEATED OXYGEN SENSOR

OK: Go to next step.

INSPECT EFI RELAY

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

Check the EFI relay resistance.

Standard:

TESTER CONNECTIONS SPECIFIED CONDITIONS (2 OF 3)

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

Reinstall the EFI relay.

Fig 3: Inspecting EFI Relay

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG: REPLACE EFI RELAY

OK: Go to next step.

CHECK HARNESS AND CONNECTOR (HEATED OXYGEN SENSOR - ECM)

Disconnect the H5 HO2 sensor connector.
Turn the ignition switch to ON.

Measure the voltage between the +B terminal of the H5 HO2 sensor connector and body ground.

Standard:

TESTER CONNECTIONS SPECIFIED CONDITIONS (3 OF 3)

Tester Connections	Specified Conditions
+B (H5-2) - Body ground	Between 9 V and 14 V

Fig 4: Identifying H5 HO2 Sensor Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Turn the ignition switch to OFF.
Disconnect the E4 ECM connector.

Check the resistance.

Standard (Check for open):

TESTER CONNECTIONS SPECIFIED CONDITIONS (FOR OPEN)

Tester Connections	Specified Conditions
HT (H5-1) - HT1A (E4-4)	Below 1 Ω
OX (H5-3) - OX1A (E4-23)	Below 1 Ω
E1 (H5-4) - Body ground	Below 1 Ω

Standard (Check for short):

TESTER CONNECTIONS SPECIFIED CONDITIONS (FOR SHORT)

Tester Connections	Specified Conditions
HT (H5-1) or HT1A (E4-4) - Body ground	10 kΩ or higher
OX (H5-3) or OX1A (E4-23) - Body ground	10 kΩ or higher

Fig 5: Disconnecting E4 ECM Connector

Reconnect the ECM connector.
Reconnect the HO2 sensor connector.

Fig 6: Sensor 1 System Diagram

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: Go to next step.

CHECK WHETHER MISFIRE OCCURS BY MONITORING DTC AND DATA LIST
NG: TROUBLESHOOT MISFIRE (See DTC P0300 RANDOM/MULTIPLE CYLINDER MISFIRE DETECTED, DTC P0301 CYLINDER 1 MISFIRE DETECTED, DTC P0302 CYLINDER 2 MISFIRE DETECTED, DTC P0303 CYLINDER 3 MISFIRE DETECTED, DTC P0304 CYLINDER 4 MISFIRE DETECTED )

OK: Go to next step.
CHECK AIR INDUCTION SYSTEM
1. Check the air induction system for vacuum leaks.
OK: No leakage from air induction system.

NG: REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK: Go to next step.
CHECK FUEL PRESSURE (See ON-VEHICLE INSPECTION )
1. Check the fuel pressure.
NG: REPAIR OR REPLACE FUEL SYSTEM

OK: Go to next step.
INSPECT FUEL INJECTOR ASSY (INJECTION AND VOLUME) (See INSPECTION )
1. Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor).
NG: REPLACE FUEL INJECTOR ASSY (See REPLACEMENT )

OK: Go to next step.
CHECK FOR EXHAUST GAS LEAKS
NG: REPAIR OR REPLACE EXHAUST GAS LEAKAGE POINT

OK: REPLACE HEATED OXYGEN SENSOR
PERFORM CONFIRMATION DRIVING PATTERN
NEXT: Go to next step.

CHECK WHETHER DTC OUTPUT RECURS (DTC P0134)

Read DTCs using the hand-held tester or OBD II scan tool.
If using a hand-held tester, select the following menu items: DIAGNOSIS/ENHANCED OBD II/DTC INFO/CURRENT CODES.
If using an OBD II scan tool, refer to the instruction manual.

Result:

RESULT REFERENCE

Display (DTC Output)	Proceed To
No output	A
P0134	B

B: REPLACE ECM (See ECM (1ZZ-FE/2ZZ-GE) )

A: Go to next step.

CONFIRM WHETHER VEHICLE HAS RUN OUT OF FUEL IN PAST

NO: CHECK FOR INTERMITTENT PROBLEMS )

YES: DTC CAUSED BY RUNNING OUT OF FUEL