2012 Ford Escape P0400 EGR Flow
In this How-to, I'll show you how to diagnose trouble code P0400: Exhaust Gas Recirculation Flow on a 2012 Ford Escape equipped with a 3.0l v6.
-1/4" drive flex head ratchet
-10mm 1/4" drive socket
-8mm 1/4" drive socket
-small flathead screwdriver
-carb/combustion chamber cleaner
1 1/16" wrench
ESTIMATED TIME REQUIRED:
STEP 1: If you have access to a scan tool with bidirectional control, start the engine and increase the EGR valve duty cycle while looking at the Manifold Absolute Pressure sensor (MAP) reading. The MAP value should increase as the duty cycle is increased. The engine should start to run rough and possibly stall out with a higher duty cycle. If the MAP sensor value doesn't increase, the EGR valve or pipe is most likely plugged with carbon deposit build- up. If this condition matches with your situation, read on.
STEP 2: Open hood, locate EGR valve. It is bolted to the back side of the intake manifold, next to the brake master cylinder. Loosen the large nut attaching the EGR pipe to the exhaust manifold.
STEP 3: Remove the 2 10mm bolts holding the EGR to the bracket on the intake manifold.
STEP 4: The EGR valve will now be free to come out, with the pipe attached. Remove the 2 8mm bolts holding the EGR bracket to the intake manifold.
Notice how the passage for the recirculated exhaust gases is plugged up solid with carbon. This is what is setting the DTC P0400. No flow can occur with this much restriction. The pipe is shaped the way it is because this EGR system relies on a vacuum venturi effect to draw the gases into the intake.
STEP 5: Using a butane torch, heat the carbon build up and then scrape it with a small flathead screwdriver. The heat will help break up the carbon, making it easier to clean. Don't direct the heat at the red oring on the pipe. Use a pipe cleaner to get deep inside and spray with carb/combustion chamber cleaner to get the rest out.
STEP 6: If there is carbon build up in the longer pipe you unbolted from the exhaust manifold, clean this pipe out as well. If you notice build up in the EGR valve itself, try to clean it too or replace it.
STEP 7: Installation is reverse of removal. Clear the DTC before starting the engine.