Expert: Roland Finston - 12/19/2011

Question
1999 Dodge Grand Caravan 164K 4-speed transmission

Coming back from a long trip and about 200 miles away from home, I stopped to get gas and the engine turned itself off at the gas station. I could start the engine, rev on idle but as soon as I put in R or D, the engine will quit. A local electrician checked for blown fuses and relays; no luck. After about 2 hours, it started working fine and I was able to get to home driving at 65-75mph. It stumbles a couple of times if the van slowed down.

I figured out that the van is working fine (more or less) when it is cold at 25-35 mph and works fine when the engine is hot at high speeds (65-75 mph). I figure this is an electrical problem or a sensor problem. The transmission is not working 100% ok as sometimes cruise control is not turning on (not even the on/off button is working). A couple of times the van just stopped working while going at around 25 mph. I had to take off the negative cable and then re-connecct and it will start running again.

Where should I look to start diagnosing the problem?

Answer
Hi Shafique,
The first order of business is to get a fault code readout of the engine and the transmission controller memories using a plug-in code reader. A nationwide autoparts store, such as Autozone, will ofter do a readout for free or you can get it done for under $40 at an independent garage. Get the specific 4-digit number, ask what they mean, what should be done, and for how much. Then send me a follow-up question and tell me the results. We'll go from there.
The experience at the gas station happened because the torque converter lock-up function got stuck in the locked up position so it was just like starting with the clutch pedal 'up' and the engine in gear with a manual shift vehicle...  It may be temporary, but I would first check that you have the proper level of fluid in the transmission via its separate dipstick. Only add ATF+4 fluid and don't overfill it.
Let me know the codes.
Roland
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