What causes O2 sensor codes?
What causes O2 sensor codes?
The Possible Causes Of Rich Codes Are: Faulty evaporative emissions system – bleeding fuel vapors into engine (not commanded by computer) On newer models a faulty fuel pump or fuel pump driver module. Faulty readings from other sensors such as a Mass Air Flow Sensor.
Is there a problem with the oxygen sensor heater?
When the codes indicate a problem with the oxygen sensor heater, that narrows the possibilities quite a bit. However, if it’s Sensor 1, even if you determine the circuits and power supply are good, simply installing a new sensor isn’t a complete fix because the powertrain control module (PCM) won’t automatically work with the new sensor heater.
How can I check if my O2 sensor is working?
One popular test is to check the amperage of the O 2 sensor’s heater circuit. This test confirms that the O 2 sensor’s heater itself is working and would lead you to believe that the vehicle is fixed. But what caused the vehicle to return two days later with the same code?
How is the O2 sensor heater circuit controlled?
The O 2 sensor’s heater circuit is controlled in one of two ways. First is the positively controlled type of circuit. If the O 2 sensor heater circuit’s negative wire goes directly to ground, look for a short-to-power problem. Usually the heater circuit in this case is controlled by a relay. Remove the relay and retest the circuit.
Are there any codes for an oxygen sensor?
There are a large number of codes relating to oxygen sensor faults. There are also a lot of faults that are often incorrectly thought to be caused by a bad oxygen sensor (also referred to as an O2 Sensor). The O2 codes relating to circuit faults can be tested fairly easily.
How to diagnose O2 sensor heater circuit failure?
The modified test harness with the light will give you easy access to the circuit. Remember, the engine needs to be running at this point. If the voltage is close to zero on the positive heater wire, then locate the open circuit in the power wire back to the fuse. Again, it may have a relay in the circuit as well.
What should I do if my O2 sensor shorted out?
In that case, first check for a blown fuse. If the O 2 sensor’s heater had shorted out, the fuse may have blown as well. Once you determine that the fuse is okay, check for voltage at the O 2 sensor harness connection. The modified test harness with the light will give you easy access to the circuit.
When does an oxygen sensor fail in a car?
As vehicles grow older, there comes a point when the oxygen or air/fuel ratio sensor’s heater circuit will probably fail. When that happens, the easiest fix is to install a new sensor. But when the vehicle comes back two days later with the same heater code, what then? A local shop called me in on just such a case.
When did I replace the O2 sensor in my van?
In February 2013, three error codes popped up (P0134, 0138, 0139), and the car was running sluggish and getting poor gas mileage. Three weeks ago, I took the van in to replace the O2 sensor. (I did not drive more than 40 miles since the codes came up).
