O2 Oxygen Sensor Upstream Downstream for Pontiac Grand Prix (1997-2003) 3.8L

Direct-Fit O2 Sensor Kit for 1997-2003 Pontiac Grand Prix (W-Body)

What it Does: This matched upstream and downstream oxygen sensor kit monitors pre- and post-cat exhaust oxygen on the 1997-2003 W-Body Pontiac Grand Prix 3.8L V6 to regulate closed-loop fueling.

The Stock Pontiac Grand Prix Sensor Failure

On the W-Body Grand Prix with the L36 / L67 3.8L V6, factory zirconia sensors endure intense thermal cycling, soot, and contamination from aging intake gaskets. Over time, the ceramic sensing element cracks from thermal shock while the internal heater circuit corrodes and opens. This causes sluggish voltage switching upstream and inaccurate catalyst monitoring downstream, forcing open-loop fueling and triggering P0134, P0135, or P0141 codes.

Common Symptoms of a Failing OEM O2 Sensor

• Check Engine Light / DTCs: Triggers P0134 (no activity) or P0135/P0141 heater circuit codes.
• Poor Fuel Economy: Sluggish switching locks open-loop enrichment, fouling spark plugs and catalysts.
• Rough Idle & Failed Emissions: Erratic fueling causes hesitation and tailpipe inspection failure.

The Direct-Fit Heated Zirconia Solution

Replacing both sensors as a matched set restores rapid closed-loop voltage switching between 0.1V and 0.9V across the exhaust stream. Each direct-fit sensor features a porous stainless shield, laser-welded housing, and fast-acting internal ceramic heater engineered to resist thermal shock and exhaust moisture. Pre-terminated 4-wire OEM connectors eliminate splicing, ensuring clean PCM signal transmission and bolt-on installation into stock L36 / L67 exhaust bungs.

What's Included

• 1 Upstream Oxygen Sensor
• 1 Downstream Oxygen Sensor

Technical Specifications

Compatibility

• 1997-2003 Pontiac Grand Prix 3.8L (Confirm engine before ordering)

Frequently Asked Questions & Fitment Warnings

Does this fit the W-Body Grand Prix?

Yes. Direct fit for the 1997-2003 Pontiac Grand Prix equipped with the 3.8L V6 (L36 / L67) engine. Excludes 3.1L V6 models; confirm your engine before ordering.

Will this clear P0135 or P0141 codes?

Yes, when caused by sensor wear or heater failure. Restores proper voltage switching to clear P0134, P0135, and P0141 once reset, provided wiring and exhaust are intact.

Is wiring modification required for installation?

No. Both sensors include OEM-style connectors for direct installation; lightly coat threads only with anti-seize before torqueing into clean bungs.

The Pontiac Precision Standard

Engineered to restore closed-loop fueling accuracy on your W-Body Grand Prix, this matched O2 sensor kit delivers consistent throttle response and emissions compliance. Keep your 3.8L V6 running CEL-free with reliable stoichiometry.