Wednesday, June 20, 2012

2001 Toyota Avalon: OBD code P0440 & P0442?

Check engine light came on vehicle.
Getting the ECM scanned showed Error codes P0440 and P0442.

Very common fail item for the older Toyota's is a faulty A/F Sensor (aka Oxygen Sensor).

Both  P0440 and P0442 codes are related to each other.
Its Emission Leak indication.
DTC P0440 or P0442 is recorded by the ECM when evaporative emissions leak from one of the components or when the vapor pressure sensor malfunctions.
Very commonly, this is a vapor pressure sensor. It should be tested for functionality.
 If it passes the test, then you should be looking for a leak in the EVAP (emissions) system. Best way to do this is to have the EVAP System "smoked". This is where a machine forces smoke through the system, and the leak will reveal itself.The Smoke test is done at most auto part garage stores.

For more help,see the parts diagram shown below:----
Toyota parts location

In this type of cases there is no "easy fix". It's a fairly straight forward code. It's either that sensor is faulty, and will need to be replaced, or there is a leak somewhere that will need to be traced and repaired. It can be traced by smoke test or pressure test.
For easy access or stat-up,you can give a visual inspection to the vacuum lines under the vehicle (shown in the image above), however, if nothing jumps out, you'll need to replace the sensor and/or find the leak.One more thing these problems are in a system that will not harm or effect engine performance in any way. Strictly for emissions control to keep the EPA happy. You can "reset" the Check Engine light by removing the "NEG terminal" cable from the battery for 15 minutes, but keep in mind, the light WILL return within 50-75 miles of combined city/highway driving.
But dont Avoid this Problems.

This details will help.

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1 comment:

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