Downstream Oxygen Sensor Lambda Probe 4-Wire for Ford Focus 2/3 C-Max, Heated Replacement
Upgrade your Ford Focus 2/3 or C-Max with a reliable downstream oxygen sensor (lambda probe) designed for precise exhaust gas monitoring. This 4‑wire, heated sensor from WEIDA AUTO PARTS is built to plug directly into your vehicle’s exhaust system, providing accurate oxygen readings after the catalytic converter. With its exact fit and OEM compatibility, it helps maintain optimal fuel trim, reduce emissions, and support smooth engine performance even as your vehicle ages.
Designed as a factory-style replacement, this downstream sensor complements the upstream sensor to deliver balanced monitoring of the exhaust system. Its piezoelectric technology ensures fast response times to changing gas compositions, helping the engine control unit adjust air-fuel mixture efficiently. The 4‑wire heated design enables faster heating of the sensor to operating temperature, which means reliable readings from cold starts and in a variety of driving conditions. OEM Number 3M51-9G444-AA ensures compatibility with Ford Focus 2/3 and C‑Max models, while origin manufacturing in Mainland China supports cost-effective, high-quality parts for maintenance and repair projects.
Benefits & Tips
- Improve fuel efficiency and reduce emissions by maintaining accurate after-catalytic-converter oxygen sensing, supporting proper engine management.
- Support reliable diagnostics and quicker resolution of check engine light related to downstream oxygen sensing by providing stable, trustworthy readings.
- Tip: When replacing, verify the OEM part number 3M51-9G444-AA matches your vehicle and follow proper installation procedures, including disconnecting the battery and respecting torque specifications for threaded connections.
Product specifications
- Brand: WEIDA AUTO PARTS
- Product type: Downstream Oxygen Sensor / Lambda Probe
- Vehicle compatibility: Ford Focus 2/3 and C-Max
- Sensor type: Piezoelectric
- Heating: Heated
- Connection: 4-Wire
- OEM No.: 3M51-9G444-AA
- Origin: Mainland China
- Measuring range: for Ford Focus 2/3 C-Max downstream installation
Package includes:
- 1 x Downstream Oxygen Sensor Lambda Probe (4-Wire)
Warnings / Reminders
- Ensure correct fitment by matching the OEM part number 3M51-9G444-AA to your vehicle.
- Disconnect the battery and follow vehicle repair guidelines during installation to avoid electrical shock or damage.
- If diagnostic trouble codes persist after replacement, inspect catalytic converter efficiency and upstream oxygen sensors as part of the full system check.
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