The engine check light came on last night in my 2000 grand caravan sport, 3.3/V6. The speedometer stoped working (stayed at zero) and the transmission failed to engage overdrive to lower the RPM's at highway speed (approx. 55mph). It seems to me that there must be an electronic module that controls the activation of the overdrivebased on thespeed/rpm levels. Has anybody encountered this problem before? I have had numerous electronic issues with this vehicle in the past such as lights and door ajar prompts going off/on periodically (I think this has to do with the electronic pickup switches on the side of the doors, but who knows, just a minor nuisance). The van also eats through brakes, etc., etc,. Most interested in the check engine light problems though. Thanks to anyone for assistance.

 

Go to Autozone and they will pull your code for you. But from what you said it is the output speed sensor. Most posts say to replace both they are under $40 for both.

 

Thanks, that's exactly what it was, the speed sensor. Great forum!