Grand Caravan - no spark

[TPringle]

This am, our 2003 Grand Caravan wouldnt start. About 6 months ago, during cold weather, it became difficult to start, but would fire after several attempts. Then, about as suddenly as it started this, it quit & hadnt missed a beat until about 3 weeks ago when the engine light came on. I had written it all off as "bad gas". Today, it refused to start. After some basic checks (ether in the air intake, and check for fire), I found it didnt have any spark. Fuel pump runs & engine light comes on. I am thinking possible a crank sensor has failed. Any experiance out there on this? I am going to run a diagnostic with a "borrowed" Autozone tester.

 

[wcjp]

Does this have a coil pack module? Individual coil packs per spark plug? Could check to see if power is making it to the module(s).

 

[Matt400]

Post back with a code, I have seen where bad crank position codes were logged in error by the ecm when the fault was actually a bad camshaft sensor. What happens is one shorts the reference voltage to ground and affects the other cuz they are on the same circuit.

 

[TPringle]

Ok, I pulled the codes, and it says there is a fault with the primary/secondary of all 3 coils. I spoke briefly to a tech at a Dodge dealer, and mentioned that I probably fine some damaged (melted) wires by the engine. I havent installed the coil pack, but have it on hand. I did not find any 12v on any pin on the 4 pin connector going to the coils. I have split the harness back several inches, but havent found any problems yet. Anyone know what pin to look for the 12v on? Is this circuit fused?

 

[Bob4x4]

Look for corrosion under the batt,it will take out the harness after a while

 

[Matt400]

Ok, I pulled the codes, and it says there is a fault with the primary/secondary of all 3 coils.

But what was the number?

Anyone know what pin to look for the 12v on? Is this circuit fused?

I will do some checking but the code may help shorten the research.

edit pin #2 brown with white tracer is 12v supply at the coil pack, it comes from the ASD relay. You might have a friend turn the key to run while you are checking this wire to see if it powers up just on the initial "key on" (not crank) because if you do it alone, the circuit will power back down when you walk over to test it.

 

[TPringle]

Ok, here are the codes: P0353, P0352, P0351 & P0456. I suppose it is like the fuel pump, and only runs for a few seconds, until the engine is cranked. It also shows a temp sensor code, but this is new since I took things apart, and I suspect I set it while it was unplugged . Thanks for the help - hopefully I can get this running again soon!

 

[Matt400]

The relay is in the IMP, (Integrated Power Module) under the hood on the drivers side.

Keep in mind though that the ECM will not allow ASD relay operation if it doesn't see a good crank signal so checking the sensor with a lab scope would be needed for that.



A bad ignition switch could also cause this fault not allowing ASD operation. I have seen battery corrosion under the battery tray cause wiring faults + some Caravans have harness troubles on top of the transaxle.



If it has an add on alarm with ignition lock out & or a remote start those are suspect too.

 

[TPringle]

I just did a check on that pin#2 and it does power up briefly when the key is switched on. I verified this several times, both with my Fluke, and once with a test lite. A crank sensor isnt very expensive, so it would be cheaper to throw one at it then to pay a shop to check it. I have a new coil pack, but am holding of on installing it until I am reasonably sure if it really needs it or not. (Be my luck, I will connect it and it will start right up! )

 

[TPringle]

After some serious studying on things, it looked like the coil mount holes on the transaxle were corroded. This led me to take a closer look at the coil pack. The metal sleeves the bolts go through were also corroded. I am asuming the coil grounds through these metal sleeves to the transaxle. After cleaning up with emory cloth, and a quick throw together test, it started up. I have since cleaned & coated with a thin coat of grease & carefully tied the wires back away from the crossover head pipe best I could. Thank you for your guidence & suggestions!