O2 Oxygen Sensor Upstream Downstream for Chevrolet Cobalt HHR (2005-2011) 2.2L 2.4L

Direct-Fit Upstream & Downstream O2 Sensor Kit for 2005-2011 Chevrolet Cobalt,HHR (Delta)

What it Does: This matched upstream and downstream O2 sensor kit for 2005-2011 Chevrolet Cobalt and HHR (Delta) L61 2.2L and LE5 2.4L engines monitors exhaust oxygen for closed-loop ECU fuel trim control.

The Stock Chevrolet Cobalt,HHR Sensor Failure

Factory oxygen sensors on the Delta chassis equipped with L61 2.2L and LE5 2.4L Ecotec engines endure severe thermal cycling and exhaust soot contamination. Over time, internal zirconia elements suffer thermal shock or additive glazing, slowing millivolt switching response. Heater circuit burnout from exhaust vibration also disrupts closed-loop fuel trim operation, triggering P0135, P0141, P0171, and catalyst efficiency P0420 fault codes. Delayed feedback forces rich fuel trims, fouling catalysts.

Common Symptoms of a Failing OEM O2 Sensor

• Check Engine Light / DTCs: Triggers P0135, P0141, or P0171 from heater failure or skewed voltage.
• Sluggish Switching & Rough Idle: Delayed response causes rich fuel trims and fouled spark plugs.
• Failed Emissions & High Consumption: Inaccurate AFR feedback reduces fuel economy and fails emissions tests.

The Direct-Fit O2 Sensor Solution

Engineered as direct-fit replacements for OEM numbers 234-4066 and 234-4342, this matched sensor kit restores factory air-fuel ratio monitoring across both exhaust positions. Each sensor features a laser-welded stainless steel housing, porous ceramic shield, and fast-acting zirconia element for rapid closed-loop transition. Factory-length harnesses and OEM-style weatherpack connectors thread directly into stock exhaust bungs without splicing wires or modifying piping. Pre-coated threads simplify installation.

What's Included

• 1 Upstream Oxygen Sensor
• 1 Downstream Oxygen Sensor

Technical Specifications

Compatibility

• Chevrolet Cobalt (2005-2006) 2.2L (L61)
• Chevrolet Cobalt (2005-2007) 2.4L (LE5)
• Chevrolet HHR (2006-2011) 2.4L (LE5)

Frequently Asked Questions & Fitment Warnings

Does this fit the Delta Cobalt,HHR?

Yes. Direct fit for 2005-2011 Chevrolet Cobalt,HHR with L61 2.2L or LE5 2.4L engines. Excludes 2.0L turbo/supercharged Cobalt SS and 2.2L HHR; confirm engine before ordering.

Will this clear P0135/P0141 codes?

Yes, if caused by sensor failure. Replacing 234-4066 and 234-4342 restores heater circuits and switching response.

Are wiring modifications needed for installation?

No. Direct-fit connectors plug into factory harnesses and thread directly into OEM bungs.

The Chevrolet Precision Standard

Engineered for Delta platforms, this matched O2 kit restores ECU fuel precision, emissions compliance, and reliable CEL-free operation.