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What Is Code P0400?

Posted By: Fluffy

What Is Code P0400? - 12/05/09 11:41 PM

2002 Dodge Durango 4.7L.


On my list, this is close as I get. Anyone have better input on what this code is for?



P0388 Crankshaft Position Sensor Supply Too High CKP sensor voltage input above the maximum acceptable voltage.
P0401 EGR System Failure Required change in air/fuel ratio not detected during diagnostic test.




Thanks.
Posted By: JH73Chal

Re: What Is Code P0400? - 12/06/09 12:06 AM

This is all I found



The exhaust gas recirculation (EGR) valve is vacuum controlled valve that regulates the amount
of exhaust gases that re-enter the cylinders. The powertrain control module (PCM) determines how
much based on engine load, temp, and other conditions. If the PCM detects that the amount of
exhaust gases entering the cylinder were insufficient or non-existent, this code is set.

Symptoms
No symptoms will likely be noticed by the driver other than the MIL (malfunction indicator lamp). However,
non visible symptoms will be increased combustion temperature and increased Nox emissions.

Causes
A code P0400 may mean that one or more of the following has happened:

Plugged EGR passage which restricts the flow of exhaust gasses
Faulty EGR solenoid
Faulty EGR solenoid wiring/harness
Vacuum lines damaged/disconnected to the EGR valve solenoid or to the EGR valve
Faulty EGR valve
Possible SolutionsSince EGR valve designs are different, no one test will suffice:

Using a scan tool, operate the EGR valve with the engine running. If the engine stumbles, the problem
was likely intermittent wiring problem or intermittent blockage problem
If engine doesn't stumble, operate the EGR valve manually, if possible. If engine doesn't stumble and die,
the ports are likely plugged. Removal of valve and cleaning of all ports will be required
Checking of solenoid can only usually be done with a scan tool, because most solenoids operate with a
duty cycle of voltage, rather than constant voltage
Check all vacuum lines, hoses, etc for any damage
Visually inspect the solenoid harness and the solenoid for damage
Replace EGR valve
Posted By: Fluffy

Re: What Is Code P0400? - 12/06/09 03:27 AM

Cool, thanks.
Posted By: dennismopar73

Re: What Is Code P0400? - 12/06/09 01:49 PM

well now
my 02 durango has the same code!!
doesnt have to do with egr valve!!

but youre crankshaft sensor does have a problem

Posted By: gtx6970

Re: What Is Code P0400? - 12/06/09 02:55 PM

Any drive / running / stalling problems?

if not clear the codes and see what comes back , if any. EGR valves are very common problems
Posted By: Fluffy

Re: What Is Code P0400? - 12/06/09 07:09 PM

No problems, just the annoying light. I've reset it and it comes back. I don't think the early 4.7's had EGR's,at least I can't find it.
Posted By: dennismopar73

Re: What Is Code P0400? - 12/07/09 12:02 AM

ok
look at the vacume lines from intake to the vapor canister
any cracks ,brokren elbows splits etc
also look on the back side of intake for broken hose
fix those you'll fix you;re lite
i have posted this before
this is a very large problem on all dodge trucks
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