Tried about thing to fix this now they say oxygen sensor are bad how can you check these and air intake sensor
have the same problem?
Wednesday, March 4th, 2015 AT 2:19 PM
What you typed doesn't make sense.
The first thing to do is list the exact fault code numbers. You didn't provide any usable information other than to say the Check Engine light is on. There's going to be diagnostic fault codes, and some of those get very specific, especially related to oxygen sensors.
You need a scanner to watch what oxygen sensors are reporting to the Engine Computer. A common problem too many people make is they replace oxygen sensors when they report a defective condition. Replacing the sensor doesn't magically correct the defect that caused the unacceptable condition to be detected. What you should see is the front, or "upstream" sensors switch between "rich" and "lean" about two times per second once the engine is warmed up. The downstream sensors might switch once per minute or two.
The intake air temperature sensor is a simple two-wire sensor. Its signal voltage can also be observed on a scanner, but you can measure it with an inexpensive digital voltmeter too. You must leave it connected for the readings to be valid. That means back-probing through the rubber seals next to the wires where they enter the plug. One wire will have 0.2 volts. The other one is the signal wire and must have between 0.5 and 4.5 volts. The higher the temperature, the lower the voltage. Failure of these sensors is extremely rare because there's just one component inside it. Fault codes are set for this one when the voltage reaches 0.0 or 5.0 volts, and that is almost always due to corrosion on the connector terminals or a cut or grounded wire. A code will be set too if the plug is disconnected while the ignition switch is on.