My 2003 Grand Caravan (3.3L) stalls after momentarily sputtering. There doesn't appear to be any relationship with warm or cold engine. Sometimes it will run fine for days and then just quit. At first, no codes were set -- then last week I got a crank ref code, so I changed the crank sensor -- no change.

I took an O-scope and probed the crank ref signal at the PCM and saw good pulses (5V, group of four pulses, then a space, then four pulses, etc.). I also probed the camshaft sensor input at the PCM and it appeared to be the IDENTICAL signal as the crank ref. I'm not sure if that is normal, I was kind of expecting a different pulse train.

I was unable to get the failure to occur while sitting there idling and looking at the signals, so I don't know if the crank ref signal is going away and causing the stall -- but the code did get set, so I'm still focusing in that area.

Additional symptom: When the failure mode is active, I can hear the fuel pump relay clicking every second (or so), as well as the AutoShutDown (ASD) relay. I pulled each relay out with the key still on and the clicking continued from the other. When the failure "corrects itself" the fuel pump relay only fires one time, then I crank and the van starts -- no problem. Sometimes the relay symptom clears on it's own, whether I leave the key on or remove the key completely, then re-engage it. This originally made me think it was a fuel-related problem.

Note -- prior to the crank code getting set, I replaced the fuel pump and filter (ouch! Its a flex-fuel unit).

My plan is to do the following (checking to see if the problem goes away after each):
1) Replace the cam sensor (based on the crank code -- I read in Mitchell's that the cam sensor might cause this code to get set).
2) Replace the water temp sensor -- hint from a buddy mechanic -- thinking that the sensor is telling the PCM that the motor is colder than it really is and delivering too much fuel???
3) Splice a wire from crank sensor to PCM.
4) Splice a wire from cam sensor to PCM.
5) ???? Any ideas???

 

Hi, I'm going through the exact same symptoms. Did you ever get this figured out? I hate to buy a bunch of sensors to replace them if they're not bad, but I don't know what else to do. I changed the crank position sensor, but that didn't help(it wasn't fun either-had a hard time finding it even).

I'm wondering if the problem isn't with one of the tire valve stem caps. I'm about ready to pull one of them off and attach a different car to it.

Any help would be appreciated.
Thanks,
Joe

 

Hey Joe,

The very next thing I tried fixed it. It was the cam position sensor. I connected a scope to each of the sensors (crank and cam) at the PCM and noticed that the pulses were identical from both sensors. This is not correct. The cam should show a sequence of pulses (one, then a group of two, followed by a group of three, etc.). At any rate, changing the cam sensor fixed it.

I know how you feel (about getting rid of it). I thought about that too -- especially when my headlights started flickering two weeks ago. (That turned out to be a connection at the PCM -- there's a connector that grounds the headlamp circuit only (and not the other marker lights)...weird.) I bent the metal tabs down in the connector so they make better contact and that problem went away.

But....payments suck, and it seems to be happy now....well, except for the power steering pump that screams like a stuck pig!! Saving that for next week.

Good luck,
Eric

 

I really appreciate your reply. I replaced the cam sensor and the van ran like a champ.

My power steering has squealed since the day they performed the recall on it. I took it back twice and they told me that it works, so they can't fix it. That whine is unbearable though.

Anyway, thanks again for your help.