Description
Maintain the engine management and emissions monitoring performance of your Lexus LS400 with the OX754 Oxygen Sensor. This product listing is intended for the Lexus LS400 UCF20R and UCF20 four-door sedan from 1994 to 2000, equipped with the 4.0-litre V8 32-valve petrol engine.
An oxygen sensor, also known as an O2 sensor or lambda sensor, measures the oxygen content in the exhaust gases and sends information to the engine control module (ECM). The ECM uses these readings as part of its engine management strategy to help regulate the air-fuel mixture and monitor emissions-control performance. Accurate sensor feedback is important for the engine to operate according to its intended calibration.
Over time, oxygen sensors can deteriorate because of high exhaust temperatures, contamination, ageing, or electrical problems. A failing sensor may provide inaccurate readings or respond too slowly, potentially contributing to a check-engine warning light, increased fuel consumption, or emissions-related diagnostic trouble codes. Replacing a sensor that has been correctly diagnosed as faulty may help restore the intended operation of the engine management system.
The Lexus LS400 4.0-litre V8 uses the 1UZ-FE engine. Depending on the model year and exhaust configuration, it may use multiple oxygen sensors serving different positions on the two cylinder banks. Confirm the exact sensor location and original part number before ordering the OX754.
Vehicle Compatibility
This listing is intended for the following application:
- Product: Oxygen Sensor
- Product Code: OX754
- Make: Lexus
- Model: LS400
- Chassis Series: UCF20R – UCF20
- Model Years: 1994–2000, as listed
- Body Style: 4-door sedan
- Engine Capacity: 4.0 litres
- Engine Configuration: V8
- Valve Configuration: 32-valve
- Engine Code: 1UZ-FE — confirm against the vehicle
- Fuel Type: Petrol
- Component: Exhaust oxygen sensor
The UCF20R designation is used for right-hand-drive LS400 applications in parts catalogues, while other UCF20 variants may differ by market and production specification. Oxygen sensor part numbers can also vary across production years and sensor positions. Verify the VIN, production date, and original equipment reference to confirm compatibility.
What Does an Oxygen Sensor Do?
The oxygen sensor monitors the oxygen remaining in the exhaust gases after combustion. The ECM interprets this information to help manage fuel delivery and monitor the performance of the emissions-control system.
The LS400 V8 can have sensors positioned before and after the catalytic converters. Upstream sensors, often referred to as Sensor 1, contribute to air-fuel control. Downstream sensors, commonly called Sensor 2, help monitor catalytic converter performance. The exact arrangement depends on the vehicle’s engine management and exhaust configuration.
Because these sensors have different functions, they should not be treated as interchangeable. Bank 1 and Bank 2 refer to the two cylinder banks, while Sensor 1 and Sensor 2 identify positions relative to the catalytic converter. The correct sensor must match the required bank, position, connector, and electrical specifications.
Key Product Benefits
Supports engine management feedback
A correctly matched oxygen sensor supplies the ECM with exhaust information used in its control strategy. If the original sensor is confirmed faulty, replacing it may help restore the intended feedback function.
Assists emissions monitoring
Oxygen sensor readings contribute to the vehicle’s emissions-control system. A suitable replacement helps provide the information needed to monitor exhaust conditions.
May help address sensor-related warning lights
A failed sensor or associated wiring circuit can trigger the check-engine light. If testing confirms the sensor itself is the cause, installing the correct replacement may help resolve the related fault.
Application-focused replacement
The OX754 listing identifies the Lexus LS400 UCF20R-UCF20 4.0-litre V8 32-valve model range. Confirming the vehicle’s production details and original part number helps reduce the risk of ordering an incompatible component.
Supports routine vehicle maintenance
Oxygen sensors operate in a demanding environment exposed to high exhaust temperatures and combustion by-products. Replacing a faulty sensor as part of a properly diagnosed repair helps maintain the intended operation of the engine management and emissions systems.
Common Symptoms of a Faulty Oxygen Sensor
A deteriorating oxygen sensor may contribute to one or more of the following symptoms:
- Check-engine warning light: The ECM may store a diagnostic code relating to the sensor signal, heater circuit, or emissions system.
- Increased fuel consumption: Incorrect readings may affect fuel-trim adjustments.
- Rough or inconsistent engine operation: Sensor-related fuel-control problems may affect engine smoothness.
- Unusual exhaust emissions: Incorrect sensor feedback or another engine fault may affect emissions performance.
- Failed emissions testing: An unresolved sensor or catalytic converter monitoring fault may contribute to a failed test.
- Stored diagnostic trouble codes: A scan tool can help identify a problem involving the sensor or its circuit.
These symptoms do not automatically mean the oxygen sensor needs replacement. Exhaust leaks, wiring damage, connector corrosion, ignition problems, fuel delivery issues, and catalytic converter faults can produce similar symptoms. A diagnostic scan and appropriate testing should be completed before installing a new sensor.
Installation Guidelines
Allow the engine and exhaust system to cool completely before beginning work. Use an appropriate oxygen sensor socket or removal tool to avoid damaging the sensor, exhaust threads, or surrounding components.
Before fitting the OX754, compare it with the original sensor. Check the connector, wire count, cable length, thread, and overall configuration. Confirm the required bank and sensor position, and verify that the replacement matches the vehicle’s VIN and original part number.
Install the sensor in the specified exhaust location and tighten it to the manufacturer’s recommended torque. Avoid contaminating the sensing element with oil, grease, or cleaning chemicals. Route the wiring away from hot exhaust parts and moving components, then secure the electrical connector.
After installation, clear diagnostic codes if appropriate and check whether the original fault returns. A suitable scan tool can help verify sensor readings and monitor related engine-management data. If the warning light remains illuminated, further diagnosis may be required.
Important Fitment Checklist
Before ordering the OX754, confirm the following:
- The vehicle is a Lexus LS400 UCF20R or UCF20.
- The engine is the 4.0-litre 1UZ-FE V8 32-valve petrol engine.
- The production date and market specification match the intended application.
- The required sensor position is confirmed: upstream or downstream.
- The correct cylinder bank is identified where applicable.
- The connector, wire configuration, thread, and cable length match the original component.
- The replacement part number is compatible with the VIN and original equipment reference.
Conclusion
The OX754 Oxygen Sensor is listed for the Lexus LS400 UCF20R-UCF20 four-door sedan from 1994 to 2000 with the 4.0-litre V8 32-valve engine. As part of the engine management and emissions monitoring systems, the oxygen sensor supplies exhaust feedback used by the ECM to support fuel control and emissions-related diagnostics.
For the best fit, verify the exact production details, original part number, and required sensor position before purchase. Since the LS400 V8 can use multiple sensors across both cylinder banks and different exhaust locations, confirming the correct application is essential. When a faulty sensor has been properly diagnosed, a correctly matched replacement may help restore the intended operation of the vehicle’s emissions monitoring system.
Reviews
There are no reviews yet.