Sensor issue

ANDERE488

MEMBER
2007 FORD FOCUS
2.0L
4 CYL
2WD
AUTOMATIC
130,000 MILES

A couple of days a go my car was having a cylinder three misfire. I replaced my cylinder three and four spark plugs. The car seemed fine and then the check engine light came on with PO400 (exhaust gas re-circulation flow) problem. We thought it might of been my MAF but because we tried the testing of it and the car stayed on when unplugged but I think that was inaccurate information. Now, since we replaced it. A new code came up with the PO400 which is PO113 (intake air temperature sensor 1 circuit high). I want to try and figure out what is wrong with my car before I go out and by another sensor or ERG valve and waste money that will not even solve my problem. What do you think the issue is?

1 Reply

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning.

The 113 code set because you disconnect the mass air flow while the engine was running. The IAT sensor is part of the mass air flow sensor.

Unplugging the mass air flow is not a test for the sensor. Voltages need to be monitored and the signal needs to be checked at different speeds and loads.

As far as the missfire, I would start by checking the compression if it comes back on.

The 400 code is EGR related and there is a sensor called the DPFE sensor that is a common failure. Below are possible causes for this code.

Roy

P0400
Item Description
Symptom/DTC P0400
Descriptor
Probable Causes:
Connector to Electric Exhaust Gas Recirculation (EEGR) Not Seated.
Electric Exhaust Gas Recirculation (EEGR) Motor Winding Circuits Shorted or Open.
Electric Exhaust Gas Recirculation (EEGR) No Voltage.
Electric Exhaust Gas Recirculation (EEGR) Valve Seat Area Carbon Build Up.
Electric Exhaust Gas Recirculation (EEGR) Valve Stuck Open or Closed.
Harness Open or Shorted to Voltage or Ground.
Mass Air Flow (MAF) Sensor Signal Erroneous.
One or More Sensors is Not Responding or Out of Range.
Vacuum Signal to Manifold Absolute Pressure (MAP) Restricted or Leaking.