Three-wire automotive O2 sensor
To check the oxygen sensor (O2S), you Testament must to apprehend the sensor's operating voltages for your specific vehicle. You may arouse this facts from your vehicle overhaul guide, your limited dealer or your resident Car parts Issue. Or you may benefit the voltage values if here for reference.2. Bare the hood and allot the O2 sensor adjacent the front exhaust channel connected to the exhaust manifold. The sensor is threaded into the front main between the manifold and the catalytic converter.
Grounds your van in a sheltered distance and balmy the engine to operating temperature. This Testament kick the O2 sensor into operating scope. Cook up confident the emergency brakes are applied, and block the front and rear wheels with wood blocks or bricks.
Then, with the advantage of a multimeter, come from this conductor to blue book and verify if the O2 sensor in your van is working properly or in necessitate of replacement.
Instructions
1. Whether your vehicle has two sensors, you Testament catch the moment one on the exhaust tube between the catalytic converter and the muffler. You may call for to hoist the vehicle to cush access to this sensor. Lift the vehivle using a floor jack and safely support it on a jack stand.3. Set your voltmeter to millivolts (mV) and back probe the O2 sensor signal wire with the meter's red lead; connect the meter's black lead to a good ground on your vehicle. A regular oxygen sensor only has one wire, while a heated oxygen sensor has three wires: signal, heater and ground. Make sure you are probing the signal wire. If necessary, consult your vehicle service manual to identify this wire.
4. Read the voltage from the sensor for about one minute with the engine running. You should get a fluctuating output voltage between 0.2 and 0.8 volts. with an average of about 0.5 volts. A voltage reading that remains low (close to 0.2 v) or high (close to 0.8) means the engine has a lean or high fuel ratio, respectively. Either the sensor is not responding, a fuel injector is leaking or clogged, or some other problem is affecting the air/fuel ratio.
5. Disconnect a large vacuum hose form the engine. Keep the engine idling and at operating temperature. The sensor's output voltage should go down to a lean condition--close to 0.2 volts. Connect the vacuum hose.
6. Snap the engine throttle open and close while reading the sensor's output voltage on the voltmeter. The sensor should cycle rapidly with the extra air.
7. Block the air inlet at the air intake system using one or more shop rags. The sensor's output voltage should go up to a rich fuel condition--close to 0.8 volts. Remove the shop rags from the air inlet.
8. Replace the oxygen sensor if its output voltage does not react to these tests.
