Ok, I just had the water pump and timing belt replaced on my 97 Caravan 3.0. Everything was running just fine, until the other day when I got stuck sitting on the highway while they were tearing up the road. Suddenly, while idling, the engine ran very rough for a momet, then the service engine soon light came on, and it returned to idling normally. This morning, I stopped by Auto Zone to ask them to pull the codes. It came back P0401 "PCM has determined that there is insufficient flow in the exhaust gas recirculation system." Where do I even start looking to determine the problem?

 

Look around the EGR valve and the area that the mechanics were working in for loose wire connectors or vacuum hoses. The computer uses the oxygen sensor to check the EGR function, if it does not see the correct change in the exhaust it's sensing it will post an error code.

 

Its pretty common to have egr faults on the RS platform. They seem to fill with carbon and stop working. and the only cure was to replace it.

 

A 97 is a NS body van.

 

check your fuel filter and or fuel pump.

 

check your fuel filters and or fuel pump, catalytic converter