Check engine light

I have a Toyota Tundra pickup, 1999, and the check engine light is on. I have recently replaced the catalytic converter, and I took it back and they said it was a P440 emission system malfunction and needed a vapor pressure sensor. Does this sound right and is it expensive?

If your vehicle does not require an emissions test, I would ignore the light. You might try disconnecting one of the battery cables for a few seconds (this will turn off the light) and see how long it stays off. Long enough to get past the emissions test? Sometimes your problem is as simple as a loose or defective gas cap.

The DTC (Diagnostic Trouble Code) P0440 is a general code for something amiss in the evaporative emissions control system. The code does not specific a particular circuit, such as the vapor pressure sensor circuit. Codes are for circuits. They are not for components.

This code, P0440, shouldn’t affect engine performance; but, since it has turn the check engine light on, if another code happens, you won’t know it because your warning, the check engine light, is already on.

I agree with Kit on this. Living with a constantly glowing SEL light totally eliminates that as an important warning of any other problem, even those that could destroy the engine.

Besides, if that light is trying to tell you that your EVAP system is not functioning properly it could be because the system is unable to breath in. If that creates a continuous high vacuum in your gas tank as the gas is pumped out, that vacuum could add stress to the pump and cause premature failure.

The EVAP system is the system through which the tank breaths in and out as gas is added and removed, and as its volume expands and contracts due to temoerature changes, agitation (vibrating fluid take up more space), etc. That vapor pressure sensor is the thing that monitors vacuum levels in the tank and tells the ECU if the pressure/vacuum gets out of range. But unless they actually measured the sensor signal itself I doubt of the sensor is the culprit.