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Missing power to ignition coil?

Tiny
MUIYEN
  • MEMBER
  • 1996 DODGE GRAND CARAVAN
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 300,000 MILES
While driving the engine stopped and I towed it to my home. I had to change Camshaft and crank shaft sensor, but it still does not work. I test circuit 44, 43, 32, 33 they are okay but when jump start, voltage signal both camshaft and crank shaft at 5 volts do not change. Test power to ignition coil, no power when crank the engine. Please someone help, which part or circuit number came from coil to before came to ECM, provide the power when turn the key or crank the engine. I have change new ECM still same. I am retired and trying to save money and my wife is very sick. Thank you
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Friday, September 16th, 2022 AT 4:15 PM

14 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

Power to the coils is from the automatic shutdown relay (ASD). The ASD is powered by fuse 12 in the under-hood fuse box. See pic 1

Pic 2 shows the relay and fuse location.

That is where I would start. If the fuse is good and has power, switch the relay with a different one having the same part number to see if that changes things.

If there isn't one, here is a link that explains how to test one:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below.
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Friday, September 16th, 2022 AT 10:12 PM
Tiny
MUIYEN
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Thank you very much Joe, I will check over, tonight I just look in diagram about ASD I think around relay and connection, hope will be good tomorrow. I wilI let you know later.
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Friday, September 16th, 2022 AT 10:58 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

You are very welcome. Let me know when you get a chance. I'm interested in knowing if you found an issue.

Take care,

Joe
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Saturday, September 17th, 2022 AT 9:25 PM
Tiny
MUIYEN
  • MEMBER
  • 8 POSTS
Hi Joe, thank you for four your kindness. Today I checked around the Auto shut down relay, fuse all good, so I have look on diagram I have, I check to from relay to number 6, number 67 for shut down relay to ECM unit, look like they still same nothing good at all, but after I check around, now I have the power at ASD relay and ignition, but when I crank the engine, it still no power from spark plug. Now the engine can't not start when I turn the key. I have to bypass the engine start relay and I think I have to check tomorrow camshaft sensor and crankshaft sensor signal and power over,
Joe that's what I think, if you have any idea, please let me know.
Thank you very much.
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Saturday, September 17th, 2022 AT 10:00 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,740 POSTS
Hi,

If the cam and crankshaft sensors are new, that is not the likely cause. I may have already asked, but do you have a live data scan tool? If you do, check to see if there is an RPM signal when cranking.

Now, if I understand correctly, the key no longer engages the starter. I'm starting to question if the ignition switch is the problem.

Take a look at the starting system circuits schematic. Check the fuses I highlighted and let me know what you find.

Take care,

Joe

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Saturday, September 17th, 2022 AT 10:30 PM
Tiny
MUIYEN
  • MEMBER
  • 8 POSTS
Hi Joe, how are you? Today I have check the diagram you gave to me, from the ignition switch to the relay, PTC circuit okay, but from the key is missing the power to relay, the switch ignition is not working. I have ordered the new switch already. Now mean time I have waiting for new coming, then I can see next. I will let you know.
Thank you
Have a good Sunday evening.
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Sunday, September 18th, 2022 AT 7:50 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

It sounds like you found the issue. I don't know if you need them, but I included the directions below for replacing the switch. If you want to confirm the switch is the issue, test for power out from the switch itself to the relay.

Let me know if you have questions or if I can help.

Take care,

Joe

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Monday, September 19th, 2022 AT 7:01 PM
Tiny
MUIYEN
  • MEMBER
  • 8 POSTS
Hi Joe, the last picture is the ignition switch. You sent to me that is the correct one, when I turn the key, relay not work, test the power, nothing appears to yellow wire to PTC number 10 3A, that why I have to order the new switch. I will let you know next.
Thank you.
Have a good night.
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Monday, September 19th, 2022 AT 7:51 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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No problem whatsoever. Let me know how things turn out or if I can help in any way.

Take care,

Joe
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Tuesday, September 20th, 2022 AT 5:47 PM
Tiny
MUIYEN
  • MEMBER
  • 8 POSTS
Hi Joe, I am still waiting for switch.
Thank you
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Tuesday, September 20th, 2022 AT 5:53 PM
Tiny
MUIYEN
  • MEMBER
  • 8 POSTS
Hi Joe, how are you? Today I have hooked up the new Ignition switch, test engine crank okay, now, fuel pump is working, just engine no spark, no power appear at B+ ignition coil pack. I use scan come up error code P0340.
Joe, I am really very confused what is wrong, where is missing the power, I have tried to look in many diagrams, but really don't know where to check?
Please help, thank you very much. Have a nice day.
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Thursday, September 22nd, 2022 AT 3:16 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

If the camshaft position sensor is bad, it can prevent spark to the plugs. Have you done anything with the sensor?

I attached the diagnostics below related to the code. Take a look through them and let me know if you are comfortable performing them.

Take care,

Joe

see pics below.
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Thursday, September 22nd, 2022 AT 7:56 PM
Tiny
MUIYEN
  • MEMBER
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Hi Joe, today I have check the picture you gave to me, camshaft and crank shaft position sensor I had replaced already, look at when key on at camshaft position sensor, It have more than 8 volts and signal sensor It got more than 5 volts, than the final, I check from camshaft sensor signal wire by ohm meter to PCM 33 It read 4ohms, with procedure say, is resistance below 5 ohms need repair the CMP sensor signal circuit for short or ground.
Mr. Joe, what do you think, do I have to replace the wire, what size wire do I need to replace?
Thank you.
Have a good evening.
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Friday, September 23rd, 2022 AT 6:51 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Hi,

Are you able to trace the wire rather than replace it? Also, have you checked the connectors for corrosion or anything that can be causing an issue?

As far as replacing it, the connectors at both ends can be a bit difficult to deal with. If I had it, I would be trying to locate the short to ground. Make sure the signal wire hasn't been pinched or pulled causing a short,

Let me know what you find.

Joe
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Friday, September 23rd, 2022 AT 9:08 PM

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