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Ron Z.
Ron Z., - Toyota Tech -
Category: Toyota
Satisfied Customers: 19039
Experience:  18+yrs experience. State Inspector and Toyota Diagnostics
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What do these codes mean...P0401 and P0441.I have already

Customer Question

what do these codes mean...P0401 and P0441.I have already replaced EGR valve and the oxygen sensor.
Submitted: 1 year ago.
Category: Toyota
Expert:  Ron Z. replied 1 year ago.

The P0401 is a flow problem in the EGR System. This is more commonly due to a faulty EGR VSV. It's located on the top of the engine. Carefully inspect the vacuum lines for any cracks, holes or disconnections. Inspect the electrical connector and wire harness for any loose, broken or damaged wires. If the visual inspection checks ok, replace the EGR VSV.

The P0441 is set when there is an evaporative emissions leak from the components or when there is a malfunction in either the VSV for EVAP, the VSV for vapor pressure sensor, or in the vapor pressure sensor itself. So, first and foremost, make sure the Fuel Cap is tight and seated correctly. Check the underside of the fuel cap for any cracks or signs of defects that may keep the cap from sealing correctly. If there are any doubts about the inspection of the cap, replace it. Keep in mind, you will need a cap that meets OE Specs. Those "universal" or "locking" fuel caps sold at after market parts stores do not meet OE specs, and will not seal the system correctly. If you are sure the cap is good and there are no leaks in the system, test the VSV's:

VSV for EVAP: 27 - 33 Ohms at 20°C (68°F)

VSV for Vapor Pressure: 33 - 39 Ohms at 20°C (68°F)

If the VSV's check ok, replace the Vapor Pressure Sensor.

With both of these codes set, I'd lean more towards a vacuum line problem seeing as the VSV for EGR an d VSV for EVAP are so close. So, inspect these lines carefully before replacing any parts. For image location view of these items, click here:

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Expert:  Ron Z. replied 1 year ago.