Minor Car Trouble

April 04, 2008 Filed in: Personal
No matter how new a car is; eventually, it will break down. 

Over the past few weeks, I’ve had my 2003 Ford Focus in and out of the shop.  Over Easter weekend, while on vacation in Savannah, GA, my “check engine soon” light came on.  It was Easter morning, just after the sun rose over Tybee Island.  It was a great morning ruined by a general feeling of “So, what’s up with my car, man?” 

There is really nothing that can be done about a malfunctioning car on Easter Sunday.  I found a Precision Tune just outside of Savannah that would be open at 8 am on Monday morning.  We had to get some friends to the Columbia, SC airport by noon, so it would be a little tight. 

After getting an oil change, the service technician found a p0401 code indicating “insufficient EGR flow.”  As someone who barely understands what happens when the oil is changed, EGR and DPFE are indeterminate terms to me.   EGR means “exhaust gas recirculation.”  It’s a system that is designed to help reduce engine emissions.  DPFE means “Delta Pressure Feedback of EGR.”  This reads the change in pressure within the EGR system. 

I mentioned to the technician that I just had the DPFE sensor replaced in October.   When the DPFE sensor goes bad, it causes a specific performance issue…mainly an engine misfire.  The initial recommendation by the technician was to have the EGR ports cleaned.  Because the problem was not a critical one and the car was still drivable, I opted to drive back to Greensboro.   When I got home, I made an appointment to have the car serviced with my normal mechanic. 

Because the DPFE sensor had been changed out in October, naturally (and myself included) everyone who looked at the car made the wrong assumption that it had to be something else in the EGR system that was going bad.  Whether it was unfamiliarity with the ZETEC engine, or just bad luck on my part, it took four separate trips (and days without a car) to figure out that the new DPFE sensor was malfunctioning.  Not the EGR valve, not the vacuum seal, not reprogramming the PCM at the Ford dealership.  These three steps were taken before replacing the sensor.

What gave me piece of mind was posting a question on www.focusfanatics.com . This site is full of Ford Focus enthusiasts who mod their engines quite a bit.  Because they modify the ZETEC engine, they know it in and out.  It turns out that the DPFE sensors on 03 ZETEC engines are notorious for going bad.  And, as the car gets older, they tend to go bad more frequently.  Thankfully, the part that was replaced was under warranty.

On the way home from the shop this evening, I noticed an overall improvement in the engine performance.  There was no stuttering or misfiring around 40 mph.  Everything seemed smooth in the engine.  I’m going to hit the highway tomorrow, so we’ll see how it does.  All in all, it’s been a trying two weeks with this car.  At least now I know where to turn when something goes awry.