1994 Dodge Caravan Engine misfire and speedometer drops

EPGOERSS

MEMBER
1994 DODGE CARAVAN
6 CYL
FWD
AUTOMATIC
146,000 MILES

The van has a 3.0 liter engine. When driving, the engine will misfire and at the same time the speedometer will drop in speed. Sometimes it drops to near 0 if it continues to misfire. When I leave off the gas pedal and then reapply it will run fine and the speedometer immediately returns to the correct speed. Sometimes it will then run well for many miles, sometimes for only a few seconds. This started happening about 6 months ago once in a while and then would be fine for days or weeks. Now it is happening almost every time I drive the van. I just did a full tune up, plugs, wires, cap, rotor, fuel filter, air filter, and oxygen sensor but it didn't help. The only error codes are 12 and 55. Does the 12 mean the controller is loosing its electrical connection or is that just the starting code? The controller has been in the van for about 2 years and the battery has not been disconnected at any time since then. Any help you can give regarding this problem is appreciated.

2 Replies

ZACKMAN

MECHANIC
4,202 POSTS

Code 12
DRB displays BATTERY DISCONNECT. Condition is: Direct battery input to Powertrain Control Module (PCM) disconnected within last 50 key-on cycles.

Code 55
DRB display will be blank. Completion of trouble code display by MIL light.

I would start by checking the battery posts and terminals. Make sure they are both free of corrosion and tight connection. Then go to your PCM (on driver side front corner of engine compartment) and make sure that the plug has tight connection and also check the ground for the PCM, as well.

I understand that the battery has nor been disconnected (on purpose), but the PCM somehow doesn't receive power from the battery intermittently.

Let me know what you find out.