1999 Ford Taurus

Hello all,

I am having two problems with my 1999 Ford Taurus that I am hoping someone can provide some guidance on:

1) Engine light stays on. I payed $80 for a mechanic to 'hook it up to the computer' to tell me that there is nothing wrong, but this light is still on. Is there an easy way to detect which sensor may have gone bad?

2) The low coolant light is now on, this occured when I had the radiator flushed and filled. The coolant level is fine, but the annoying light is on.

Thanks in advance for any assistance that you can provide.

For the check engine light, if it is yellow, go to a chain auto parts house(Autozone, Pep Boys), they will read the codes dor you. Write the code numbers down and post them back here. Be sure you have the exact numbers.
For the low coolant, there is a sensor in the bottom of the coolant reservoir that tells when you are low. make sure it is connected. if it is, the sensor is probably bad.

The error code is P0401 Exaust Gas Recirculation Flow Insufficient Detected.

Thanks for the help!

95% of the time the P0401 is the DPFE sensor. It is easily replaced and costs around 50$ more or less. Also there are ports under the EGR valve that will plug and cause this code.