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I have a 2005 cobalt with no spark at the coils but I do…

I have a 2005 cobalt...
I have a 2005 cobalt with no spark at the coils but I do have rpm and injector pules, I work with a another Mech from your J.A's, the last contact he had me check between the 3rd and 4th pin for a pulse using a noid light. Q on the coil plug I have a pink wire that's hot (key on), black (ground) a brown and white wire I think this is the reference wire, a white and a orange wire I think is for timing. I placed my light between the pink and b/w wire and there's no flash, I want to make sure this procedure is correct, also what wire to ck coming straight of the ecm
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Answered in 4 hours by:
10/18/2017
AMEDEE
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 27,308
Experience: ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
Verified

Hello and welcome!

My name isCustomerand I can assist you with your question.

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Would a wiring diagram of your ignition system help?

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Customer reply replied 4 months ago
I guess I just want to make sure I done all check before I order a ecm. also could you tell me and from my understnding 2005 dosen't have the security key its a base model cobalt

A security key? You mean security system?

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Customer reply replied 4 months ago
with the chip in the key

Got it! Thank you for clearing that up.

One moment while I type your reply

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This system uses a passlock sensor inside the ignition lock cylinder or housing. It is not in the key.

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Customer reply replied 4 months ago
just trying to make sure its not the key or something in that range, I didn't think so because I have injector pulse? if that's correct can you give the color wire coming out of the ecm that should be sending the coil the signal to fire and maybe the wiring diagram there no good ones on line

YES sir. One moment please

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Customer reply replied 4 months ago
I would appreciate your thought I think I need a ecm?

Most certainly.

Is it possible the ECM is faulty? YES, it is.

Is it common? No, it is not.

The trigger wires for the ignition system between the ECM and ignition module are the white wire and the orange wire.

If the crank sensor signal is good going into the ECM and the ECM is powered up and awake during cranking and sees engine rpm but is not triggering the circuits going to the ignition control module, then yes the ECM is faulty and will need to be replaced.

I have attached a wiring diagram of this circuit below.

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Customer reply replied 4 months ago
can I put a noid light between 12v and the white or orenge and it should flash?

These circuits get a 0 to 5 volt square waveform from the ECM when cranking (or when running).

I would think the other end of the noid light or test light should go to ground. Then as it gets pulsed to 5 volts, it will blink as the engine rotates.

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Customer reply replied 4 months ago
I see so what is the brown/white wire?

That would be the cam sensor signal wire.

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Customer reply replied 4 months ago
OK the last JA expert had me place my noid between the 12v and the b/w and look for flashing is this correct?

YES, that should still work. The reason being is because as the engine rotates and the signal gets toggled to 0, it will illuminate the light.

However, I would recommend to try it both ways just to be sure.

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Customer reply replied 4 months ago
OK I will as of right know I don't have signal there THANKS

Your welcome!

I am glad I can help!

Please don't forget to honor your good faith deposit by rating my answer as "5 STARS or SMILEY FACES" for assisting you today.

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Please let me know if you have any further questions.

Thanks and have a great night!!

AMEDEE
AMEDEE, CHEVY TECHNICIAN
Category: Chevy
Satisfied Customers: 27,308
Experience: ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
Verified
AMEDEE and 87 other Chevy Specialists are ready to help you
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Customer reply replied 4 months ago
Hey I have one more q

Yes sir I am here

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Customer reply replied 4 months ago
I was in process of ordering a ECM for this vehicle and the salesperson is convinced I nave a key program problem I need to know dose this 2005 cobalt have a programmed Key and if so could this cause this kind of problem, keep in mind I have injector pulse but no pulse to the coil.

No sir, this is not related to the security system.

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Customer reply replied 4 months ago
OK thanks for getting back with me! :)

You are most welcome!

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Customer reply replied 4 months ago
Hi. i have a question if I need to pay more let me know, I replaced the ecm om this car from a auto computer co. online and I did the relearn for the key but I have a code for po315 crank sensor relearn, will this code keep it from starting?

YES sir I believe so.

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Customer reply replied 4 months ago
I believe this has to done with a scan tool with that capability?

Sorry, my mistake. I thought this was for the security system. Does the engine have spark while cranking?

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Here is the definition for this code.

P0315 Crankshaft Position Sensor Variation

Possible Causes

  • Ignition switch is on, but the battery has insufficient voltage
  • PCM power disconnected with key on (this action erases the learned values)
  • Crankshaft main bearings worn or reluctor wheel is damaged
  • Crankshaft run-out is excessive or the crankshaft is damaged
  • Debris that passes between the CKP sensor and reluctor wheel
  • CKP sensor signal circuit has an interference condition (EMI)
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Customer reply replied 4 months ago
I think I'm still at square on I have injector pulse but no coil, that's why I was asking, this car ran before I changed the motor all the sensors where the same?

Ok, at this point, I think we need to speak on the phone.

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Customer reply replied 3 months ago
Hey a little FYI I found the problem with that vehicle, GM uses a multi ground connector to the front of the transmission and even though that connector looked good I cut the connector off and crimped and sutured a new end on, I borrowed a better scan tool then my reader a GM tech 2, I noticed every time I tried to start the car it would go out so I started looking for ground places. Thanks for your time.

YUP! That will do it! Glad to hear it is all fixed!

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AMEDEE
AMEDEE, CHEVY TECHNICIAN
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Satisfied Customers: 27,308
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Experience: ASE certified tech ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector

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