How to Replace the Oxygen Sensor on an HHR

by Joshua Benjamin
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old car image by Alexander Ivanov from

An oxygen (O2) sensor is a small device that helps your vehicle's onboard computer monitor and adjust the proportions of air and fuel in your engine. The Chevrolet HHR crossover SUV has two oxygen sensors, one on the exhaust manifold just to the front (toward the engine) of the catalytic converter, and one directly behind the catalytic converter. Replacing one of these oxygen sensors is fairly simple.

Step 1

Locate the O2 sensor you wish to replace, near the catalytic converter on the exhaust manifold. The sensor looks like a golden peg with wires coming out of it.

Step 2

Disconnect the wires by hand from where they hook into the HHR's electrical system. Take care not to damage the electrical socket, as you will need to plug the new O2 sensor back into it. But don't worry about damaging the O2 sensor's wires; you won't be reusing them.

Step 3

Use a wrench or ratchet and socket to loosen and unscrew the O2 sensor. Use extra force if you haven't changed out the O2 sensor for a long period of time. Safely discard the sensor.

Step 4

Spray the threads of your new O2 sensor with WD-40 or a similar lubricant, and then do the same to the threads of the screw-in hole from where you removed the old O2 sensor. This will ensure that you can screw the sensor in smoothly and without having to force it--which could potentially damage the threads.

Step 5

Use your wrench or ratchet and socket to screw the new O2 sensor into place, and tighten the sensor down securely. Connect the wires to the appropriate electrical socket.

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