3Uz-Fe Engine Control System. Dtc P0134 Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

The heated oxygen sensor is used to monitor oxygen concentration in the exhaust gas. For optimum catalytic converter operation, the air-fuel mixture must be maintained near the ideal stoichiometric air-fuel ratio. The heated oxygen sensor output voltage changes suddenly in the vicinity of the stoichiometric air-fuel ratio. The ECM adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The heated oxygen sensor generates a voltage between 0.1 and 0.9 V in response to the oxygen concentration in the exhaust gas.
If the oxygen concentration in the exhaust gas increases, the air-fuel ratio is called LEAN. The heated oxygen sensor voltage drops below 0.45 V, which informs the ECM of the LEAN condition.
If oxygen is not in the exhaust gas, the air-fuel ratio is called RICH. The heated oxygen sensor voltage increases above 0.45 V, which informs the ECM of the RICH condition.

Lexus Gs430, Gs300. Uzs190 Grs190.3Uz-Fe Engine Control System.Sfi System.
Dtc
P0134 Oxygen Sensor Circuit No Activity Detected (Bank 1 Sensor 1)

HINT:

The ECM provides a pulse width modulated control circuit to adjust current through the heater. The heated oxygen sensor heater circuit uses a relay on the +B side of the circuit.

DTC No.	DTC Detection Condition	Trouble Area
P0134 P0154	After engine is warmed up, heated oxygen sensor (sensor 1) does not indicate RICH (greater than 0.45 V) even once when conditions (a), (b), (c), (d) and (e) continue for 20 seconds (1 trip detection logic): (a) Engine speed: 1,400 rpm or more (b) Vehicle speed: 40 km/h (25 mph) or more (c) Throttle valve is not fully closed (d) 180 seconds or more after starting engine (e) ECT is more than 40°C (104°F)	Open or short in heated oxygen sensor (sensor) circuit Heated oxygen sensor (sensor 1) PCV valve and hose Air induction system Fuel pressure Injector Gas leakage in exhaust system EFI MAIN relay ECM

HINT:

Confirm the heated oxygen sensor (sensor 1) voltage. Enter the following menus: Powertrain / Engine / Data List / Primary / O2S B1 S1 (or O2S B2 S1).

If the voltage is less than 0.1 V, the sensor circuit may be open or short.

MONITOR DESCRIPTION

The ECM uses the heated oxygen sensor to optimize the air-fuel mixture with closed-loop fuel control. This control helps decrease exhaust emissions by providing the catalyst with a nearly stoichiometric mixture. The sensor detects the oxygen level in the exhaust gas and the ECM uses this data to control the air-fuel ratio. The sensor output voltage range is from 0.1 V to 0.9 V. If the signal voltage is less than 0.45 V, the air-fuel ratio is LEAN. If the signal voltage is more than 0.45 V, the air-fuel ratio is RICH. If the sensor does not indicate RICH at least once despite the conditions for the closed-loop fuel control being met and the specified time period has passed, the ECM will conclude that the closed-loop fuel control is malfunctioning. The ECM will illuminate the MIL and a DTC is set.

WIRING DIAGRAM

CONFIRMATION DRIVING PATTERN

Connect the intelligent tester to the DLC3.
Allow the engine to idle until ECT reaches 40°C (104°F).
Allow the vehicle to run at 60 km/h (38 mph) or more for 3 minutes or more.

INSPECTION PROCEDURE

HINT:

It is possible the malfunctioning area can be found using the Active Test Control operation. The Active Test can determine if the heated oxygen sensor or other potential trouble areas are malfunctioning or not.

The injection volume can be switched to -12.5% (decrease) or +25% (increase) by the Active Test.

The Active Test procedure enables a technician to check and graph the output voltage of the heated oxygen sensors.

Procedure:

Connect the intelligent tester to the DLC3.
Turn the engine switch on (IG).
Warm up the engine by running the engine at 2,500 rpm for approximately 90 seconds.
Enter the following menus: Powertrain / Engine / Active Test / Control the Injection Volume.
Perform the Active Test while the engine is idling.

Standard:: The heated oxygen sensor reacts in accordance with the increase and decrease of injection volume:
+25% → RICH output: More than 0.55 V
-12.5% → LEAN output: Less than 0.4 V

NOTICE:

The heated oxygen sensor (sensor 1) output has a few seconds of delay and the heated oxygen sensor (sensor 2) output has a maximum of 20 seconds of delay.

If the vehicle is short on fuel, the air-fuel ratio becomes LEAN and the DTCs will be recorded.

Case	Heated Oxygen Sensor Voltage (sensor 1)	Heated Oxygen Sensor Voltage (sensor 2)	Main Suspected Trouble Area
1	Injection Volume +25% -12.5%	Injection Volume +25% -12.5%	-
1	Heated Oxygen Sensor Voltage 0.55 V or more Below 0.4 V	Heated Oxygen Sensor Voltage 0.5 V or more Below 0.4 V	-
2	Injection Volume +25% -12.5%	Injection Volume +25% -12.5%	Heated oxygen sensor (sensor 1) Heated oxygen sensor heater (sensor 1)
2	Heated Oxygen Sensor Voltage Almost no reaction	Heated Oxygen Sensor Voltage 0.5 V or more Below 0.4 V
3	Injection Volume +25% -12.5%	Injection Volume +25% -12.5%	Heated oxygen sensor (sensor 2) Heated oxygen sensor heater (sensor 2)
3	Heated Oxygen Sensor Voltage 0.55 V or more Below 0.4 V	Heated Oxygen Sensor Voltage Almost no reaction
4	Injection Volume +25% -12.5%	Injection Volume +25% -12.5%	Injector fuel pressure, Exhaust gas leak, etc. (air-fuel ratio is extremely LEAN or RICH)
4	Heated Oxygen Sensor Voltage Almost no reaction	Heated Oxygen Sensor Voltage Almost no reaction

HINT:

Read freeze frame data using the intelligent tester. 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.
Bank 1 refers to the bank that includes cylinder No. 1.
Bank 2 refers to the bank that does not include cylinder No. 1.
Cylinder No. 1 is located in the front part of the engine, opposite the transmission.
Sensor 1 refers to the sensor closest to the engine body.

1.CHECK OTHER DTC OUTPUT

Connect the intelligent tester to the DLC3.

Enter the following menus: Powertrain / Engine / DTC.

Read the DTCs.

Result:

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

GO TO RELEVANT DTC CHART

A

2.READ DATA LIST (HEATED OXYGEN SENSOR (SENSOR 1) VOLTAGE)

Connect the intelligent tester to the DLC3.

Enter the following menus: Powertrain / Engine / Data List / Primary / O2S B1 S1 (or O2S B2 S1).

Allow the engine to idle until the ECT reaches 40°C (104°F).

Quickly depress the accelerator pedal 3 times until the engine RPM reaches 4,000 rpm. Then, read the heated oxygen sensor (sensor 1) voltage.
Standard voltage:
The heated oxygen sensor (sensor 1) voltage is 0.45 V or more at least once.

Go to step 11

NG

3.CHECK CONNECTION PCV HOSE

OK:: PCV hose is connected correctly and is not damaged.

REPAIR OR REPLACE PCV HOSE

OK

4.INSPECT HEATED OXYGEN SENSOR

Disconnect the E23 and E44 sensor connectors.

Measure the resistance of the sensor.
Standard resistance:
Tester Connection
Specified Condition
1 (HT1A) - 2 (+B)
11 to 16 Ω
1 (HT2A) - 2 (+B)
11 to 16 Ω
1 (HT1A) - 4 (E2)
10 kΩ or higher
1 (HT2A) - 4 (E2)
10 kΩ or higher

REPLACE HEATED OXYGEN SENSOR

OK

5.INSPECT INTEGRATION RELAY (EFI MAIN)

Remove the integration relay from the engine room No. 2 junction block.

Measure the resistance of the EFI MAIN relay.
Standard resistance:
Terminal Connections
Specified Condition
2A-8 - 2C-1
10 kΩ or higher
2A-8 - 2C-1
Below 1 Ω
(when battery voltage is applied to terminals 2A-6 and 2A-7)

REPLACE INTEGRATION RELAY

OK

6.CHECK WIRE HARNESS (HEATED OXYGEN SENSOR (SENSOR 1) - ECM)

Disconnect the E23 and E44 sensor connectors.

Disconnect the E6 and E8 ECM connectors.

Measure the resistance of the wire harness side connectors.

Standard resistance:

Tester Connection	Specified Condition
E23-1 (HT1A) - E8-24 (HT1A)	Below 1 Ω
E23-3 (OX1A) - E8-30 (OX1A)	Below 1 Ω
E44-1 (HT2A) - E6-5 (HT2A)	Below 1 Ω
E44-3 (OX2A) - E6-28 (OX2A)	Below 1 Ω
E23-1 (HT1A) or E8-24 (HT1A) - Body ground	10 kΩ or higher
E23-3 (OX1A) or E8-30 (OX1A) - Body ground	10 kΩ or higher
E44-1 (HT2A) or E6-5 (HT2A) - Body ground	10 kΩ or higher
E44-3 (OX2A) or E6-28 (OX2A) - Body ground	10 kΩ or higher

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

7.CHECK AIR INDUCTION SYSTEM

Check the air induction system for vacuum leaks.
OK:
There are no vacuum leaks in air induction system.

REPAIR OR REPLACE AIR INDUCTION SYSTEM

OK

8.CHECK FUEL PRESSURE

Check the fuel pressure (Click here).

REPAIR OR REPLACE FUEL SYSTEM

OK

9.INSPECT FUEL INJECTOR

Check the injector injection (whether fuel volume is high or low, and whether injection pattern is poor).

REPLACE FUEL INJECTOR

OK

10.CHECK FOR EXHAUST GAS LEAKAGE

OK:: No gas leakage.

REPAIR OR REPLACE EXHAUST SYSTEM

REPLACE HEATED OXYGEN SENSOR

11.PERFORM CONFIRMATION DRIVING PATTERN

HINT:

Clear all DTCs before performing the confirmation driving pattern.

NEXT

12.READ OUTPUT DTC (DTC P0134 OR P0154 IS OUTPUT AGAIN)

Clear the DTC (Click here).

Start the engine and allow the engine to idle for 15 seconds or more.

Read the DTC.

Result:

Display (DTC output)
Proceed to
None
A
P0134 or P0154
B

REPLACE ECM

A

13.CONFIRM IF VEHICLE HAS RUN OUT OF FUEL

If the vehicle has run out of fuel, proceed to A.

If the vehicle has not run out of fuel, proceed to B.

CHECK FOR INTERMITTENT PROBLEMS

DTC IS CAUSED BY RUNNING OUT OF FUEL

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

Tester Connection	Specified Condition
1 (HT1A) - 2 (+B)	11 to 16 Ω
1 (HT2A) - 2 (+B)	11 to 16 Ω
1 (HT1A) - 4 (E2)	10 kΩ or higher
1 (HT2A) - 4 (E2)	10 kΩ or higher

Terminal Connections	Specified Condition
2A-8 - 2C-1	10 kΩ or higher
2A-8 - 2C-1	Below 1 Ω (when battery voltage is applied to terminals 2A-6 and 2A-7)