engine idles up and down after it warms up, put on new egr valve but still lighting up check engine light to code PO401
Sep 25, 2008 at 4:05 PM
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BMRFIXIT
✓ASE Certified Mechanic
19,053 POSTS
Possible causes:
vacuum supply
EGR flow path restricted
VREF open to DFE
DFE EGR sensor no good
check DPF egr sensor hoses
Sep 25, 2008 at 5:17 PM
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