Workshop Manual

6E–301
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0401 – EGR Flow Insufficient
Step Action Value(s) Yes No
1 Was the “On-Board Diagnostic (OBD) System Check”
performed?
— Go to Step 2
Go to OBD
System
Check
2 Is DTC P1404 also set?
—
Go to DTC
1404
Go to Step 3
3 1. Start the engine.
2. Monitor the MAP signal with a Tech 2 while idling.
3. While idling, jab the accelerator pedal about halfway
down and immediately let the engine return to idle.
Did the MAP value on the Tech 2 show an immediate
large change?
— Go to Step 5 Go to Step 4
4 Replace the MAP sensor.
Is the action complete?
— Verify repair —
5 1. Inspect the exhaust system for modification of
original installed parts or leaks.
2. If a problem was found, repair exhaust system as
necessary.
Was a condition present that required repair?
— Go to Step 8 Go to Step 6
6 1. Remove the EGR valve.
2. Visually and physically inspect the pintle, valve
passages and the adapter for excessive deposits or
any kind of a restriction.
3. If a problem is found, clean or replace EGR system
components as necessary.
Was a condition present that required repair?
— Go to Step 8 Go to Step 7
7 1. Remove the EGR inlet and outlet pipes from the
exhaust manifold and the intake manifold.
2. Inspect the manifold EGR ports and the EGR inlet
and outlet pipes for a blockage caused by excessive
deposits or other damage.
3. If a problem is found, correct the condition as
necessary.
Was a condition present that required repair?
— Go to Step 8
Refer to
Diagnostic
Aids
8 1. Review and record the Tech 2 Failure Records data.
2. Clear DTC and monitor the Tech 2 System Info
Screen while operating the vehicle as specified in
“Diagnostic Aids”.
3. Using a Tech 2, monitor “DTC” info for DTC P0401
until the DTC P0401 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P0401 failed this
ignition?
— —
Repair
complete