Danger

1999 Taurus v6


So heres the deal...check engine lights been on for about 4 years now. (not my car) Keep getting the p1401 code. Car runs and idles fine, just poor gas mileage. I replaced the egr valve and the dpfe sensor to no avail. Light stays off when reset for seemingly unlimited mileage and comes back on when car is restarted. So the question is, where do I go next? Someone had told me clogged cats could cause this but that will likely be the most expensive route or replacement. So any ideas would be much appreciated!!

SHOZ123

DPF EGR circuit open
VREF short to PWR
Damaged DPF EGR sensor
DPFEGR circuit short to PWR
SIG RTN circuit open
Damaged PCM

Danger

ok most of that I get except the sig rtn circuit. What is that? And how do I check these things other then looking for damaged wiring? If it were the pcm, seems like there would be substancial other problems, but I could be wrong.

SHOZ123

Signal return is the 5v coming back. It will not be 5 volt though but a lesser value depending on the DPFE output. You can back probe the PCM connector or the DPFE connectorand test the voltages with a mulitmeter. Of course you have to know which wire it is. Seldom are the PCMs bad but it does happen.

btlwgn98

This might seems ridiculous, but it was a problem i had in trying to fix p0401...when i replaced the sensor, (i'm guessing from metal to plastic, right?) it started throwing p1401. Took the sensor back off and looked it over, one of the elec. connections was bent out of place. Seriously, the easiest fix ever, pliers, or just take the part back under its warranty (24 months @ autozone). Solved my p1401. any suggestions on solving my p0401???? just kidding, already started a post for that.