Buy Acura CL Oxygen Sensors

The oxygen sensor-also called an O? sensor, lambda sensor, or air-fuel ratio sensor-is a small probe in your Acura CL's exhaust that tells the engine computer how much oxygen is in the hot gases. When it works, it helps the car burn fuel cleanly, saves gas, and keeps the "Check Engine" light off. When it fails, you may notice rough running, poorer mileage, or a failed smog test. The 4-cylinder CL uses two sensors (one before and one after the catalytic converter), while the V-6 models use four (one pair for each bank). Typical service life is about 90,000-100,000 miles, and the part threads in at roughly 33 ft-lb of torque. Federal law protects many emissions parts-including O? sensors-for up to eight years or 80,000 miles. Everything below dives into what the sensor does, how to spot trouble, how to replace it, and answers to the most common questions.

An oxygen sensor produces a tiny voltage that changes as the exhaust flips between rich and lean mixtures; the engine control unit "reads" this signal hundreds of times a second to keep fuel burn near the ideal 14.7:1 air-fuel ratio Oxygen sensor basics.
Modern "heated" sensors warm up fast so they start working within seconds of startup, cutting cold-start pollution .
Some performance tuners swap in a wideband sensor, which can read a much broader range of mixtures for precise fuel mapping wideband overview (Wikipedia).

• Upstream (Sensor 1): Screwed into the exhaust manifold or just below it, before the catalytic converter.
• Downstream (Sensor 2): Mounted after the catalytic converter to monitor converter efficiency.
• V-6 models (2001-2003 Type-S and base): Bank 1 sensors are on the firewall side; Bank 2 on the radiator side (acura enthusiast guide) (Acurazine).
  A short video walk-through helps visualize typical placements see demo (YouTube).

• Flashing or steady Check Engine light with codes P0131, P0134, P0141, P0420, etc. (AutoZone.com, Firestone Complete Auto Care)
• Drop in fuel economy-often 10 % or more.
• Rough idle, hesitation, or misfires because the mix runs too rich or too lean.
• Failed emissions or state inspection.

Heated zirconia sensors usually last around 90k-100k miles, though exposure to oil, coolant, silicone sealant, or leaded fuel can shorten life (acura owner poll) (Acurazine). Many DIYers choose to replace upstream sensors proactively every 100k miles to maintain mileage.

Under the federal Clean Air Act, specified major emission parts are covered for 8 years/80,000 miles. While O? sensors are not always on that short list, many Acura CL models built for California or similar states include them in the extended coverage booklet; always check your warranty manual EPA FAQ.

1. Cool Down: Exhaust must be under 100 °F to avoid burns.
2. Unplug Connector: Follow the wire to its plug; press the lock and separate.
3. Remove Sensor: Use an O?-sensor socket plus breaker bar; apply penetrant first if rusty.
4. Install New Sensor: Hand-thread to avoid cross-threads; tighten to about 33 ft-lb (44 N·m) service torque chart.
5. Clear Codes: A scan tool or brief battery disconnect resets the light.

Tip: Most new sensors come with anti-seize on the threads; adding extra can foul readings, so only use manufacturer-approved compound general torque reference.

? scroll table horizontally ?

Data reflects factory service literature and enthusiast guides (Acurazine).

A healthy lambda sensor helps the catalytic converter cut harmful carbon monoxide, hydrocarbons, and nitrogen oxides by over 90 % catalytic converter overview. A failing sensor can push emissions well above legal limits, leading to fines or a denied registration test. Proper function also saves gasoline-often 1-2 mpg-reducing both fuel cost and CO? footprint.

Enthusiasts who install cold-air intakes, headers, or forced induction often add a wideband UEGO sensor plus gauge. The wideband can read rich mixtures down to 10:1 and lean up to 22:1, letting tuners dial fuel and ignition safely on a chassis dyno SAE research note. Remember: tampering with emissions equipment on street cars can violate federal and state laws.

• Use only sensor-safe RTV when sealing exhaust joints; silicone can poison the sensing element.
• Never drop a sensor-the ceramic core is fragile.
• For stubborn sensors, heat the bung with a propane torch to expand metal and break carbon bonds, then remove.
• Coat the harness connector with dielectric grease to keep moisture out.

Q: How many oxygen sensors does my 2003 CL Type-S have?
A: Four-an upstream and downstream sensor for each bank of the V-6 (Acurazine).

Q: Can I drive with a bad O? sensor?
A: The car will run, but fuel economy and emissions suffer, and it can damage the catalytic converter if left unchecked (AutoZone.com, Firestone Complete Auto Care).

Q: What is the correct torque when installing a new sensor?
A: About 33 ft-lb (44 N·m) on most Honda/Acura threads (Honda Tech).

Q: Do I need special tools?
A: A slotted O?-sensor socket helps clear the wire, plus a torque wrench for proper tightening.

Q: Why does my sensor have four wires?
A: Two are for the heating element; the other two carry the signal back to the engine computer (Wikipedia).

Q: What causes premature sensor failure?
A: Oil or coolant leaks, silicone sealants not rated "sensor-safe," leaded fuel, or driving through deep water that cracks the ceramic.

Q: Will premium gas make the sensor last longer?
A: Not directly; clean fuel and proper maintenance matter more than octane rating.

Q: Is the sensor covered by warranty?
A: Emissions coverage is at least 2 years/24,000 miles; some models list O? sensors under the 8-year/80,000 mile federal warranty (US EPA).

Q: How do I clear the "Check Engine" light after replacement?
A: Use a scan tool to erase codes, or disconnect the battery for five minutes (this also resets radio presets).

Q: Are upstream and downstream sensors interchangeable?
A: No. Upstream units are precise narrow-band devices; downstream ones monitor the catalytic converter and may have different calibration.

A working oxygen sensor is a tiny part that makes a big difference in how your Acura CL drives, how much fuel it drinks, and the pollutants it releases. Replacing it on time is a quick win for your wallet, the engine, and the environment. By following the simple checks and steps above, you can keep that "lambda lifeguard" doing its job for years to come.