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Q: I own a 1997 Dodge Caravan 3.3 liter V-6. The check-engine light came on and the code was P0401 low EGR flow. The mechanic replaced all the parts in the EGR system and said the system is working as designed. He said the computer may have to be reprogrammed. What are your thoughts?
A: I see this problem on vehicles often. Just because there is a fault code for a particular system does not necessarily mean the problem is in that circuit or system. On your particular case the problem could be a slow (lazy) front oxygen sensor. A normal operating oxygen sensor voltage will change as soon as the EGR opens and closes. A lazy front oxygen sensor is operating fast enough not to set an oxygen sensor code, but not fast enough to see the EGR valve is opening and closing as it should.
- Junior Damato, Talking Cars columnist
GateHouse News Service
