Dodge Repair/'02 Grand Caravan hard to start
My 2002 Dodge Grand Caravan is difficult to start. The engine turns over, but it will either start immediately or I can crank it forever without it catching. Every so often, it will throw a code - P1684 - which seems to be a battery disconnect, though I haven't disconnected the battery. The engine never fails to crank (power to the starter, normal crank sounds, etc), but it only catches one out of every 3-4 tries. When it catches, it's in about 1 second of cranking. Any ideas? Thanks so much for your help!
There are several possibilities:
There could be a sensor or other component that is out of spec but no so badly as to set a code. That would only be found by a more detailed scan with a diagnostic readout box which you may want to do after checking out these other possibilities.
There may be a wire at the battery + post (orange) that may be corroded and thus has an intermittent connection to the body computer/instrument cluster which is sensed and when so it sets the 1684 code. So check that orange wire (actually it is a 'fusible link' for that possibility. When it won't start test for 12V at fuse 24 which is what that orange fusible link is connected to.
The exhaust gas recirculation valve may be gummed up such that it is failing to close tightly when you turn off the engine. Then when you go to start it later that valve being ajar cause a too lean mixture to sustain an idle. The easiest fix for that is to go to the valve and spray some WD-40 on the stem of the valve where it enters the valve body. It is located behind a flange that separates the body of the valve from the round vacuum-operated actuator and thus can hide the stem from your view. After spraying the stem move it back and forth via the tip of a screwdriver inserted into the slot that circumscribes the stem. This can be happening without setting a fault code. It also manifests this behavior by causing the engine to stall as you slow down to a stop which again is a time when the valve has to close tightly.
Sorry for the delay in answering but I just found your question in the 'poll' to which it had been referred by the other expert, Kevin.
Please read the PS below.