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•
A faulty EGR valve may cause:
– Black smoke
– Low power
– Rough running under a load
– Hesitation or surge
•
Many things can indicate the EGR valve is not operating properly, for example:
– Seeing code 238 and code 478 together indicates the turbocharger is stuck in a full boost.
– Code 404 for an EGR valve could be caused by a sticking turbocharger. This could cause the EGR valve to
flutter and not hold a steady state.
•
A faulty EGR valve will not cause:
– White smoke
– Blue smoke
– No start
– Rough running at idle
NOTE: The EGR valve may not begin to move until approximately 40% EGRDC.
•
Another recommended recording is the EGRVP at 50% duty cycle on the upward travel and the downward
travel.
– Look for a smooth transition in the valve position through the range of commands.
– A sudden jump after no noticable movement can indicate a sticky valve.
•
An EGR operation quick check is to look at the IAT1 and IAT2 temperatures.
– Normal is to see approximately 100°F difference in the temperature between IAT1 and IAT2
– An open EGR valve may show a 200°F difference.
EGR Position Test
Percent Open
0%
90-100%
Travel
FIRTFT 6.0L Diesel Engine EGR System
LESSON 3: DIAGNOSTICS
Voltage
0.4-1.2
3.3-4.7
2.71
27-OCT-04
Position
Closed
Open
Minimun travel
3-5
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