has no spark

2000 CHEVROLET ASTRO
168,450 MILES
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LINDOPARK
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The CKP signal is there to the PCM but there is no trigger signal at the ICM. There are NO codes displayed.

The van cranks well. I have wiring diagrams and have confirmed continuity between CMP, ICM, CKP to PCM. The problem seems to be that the PCM is not outputting the ICM trigger signal. Is there a security system issue which could be interrupting this signal and if so, how do I correct this.

David
Apr 24, 2012 at 3:32 PM
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DOCFIXIT
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Check engine light on? Theft deterant light on?
Apr 24, 2012 at 6:35 PM
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LINDOPARK
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Check engine lamp and security lamp are on briefly as usual but go off after a few seconds and my scan tool displays no trouble codes.I tried setting a code by disconnecting various sensors and then cranking the motor over. Even after doing so, scan tool displays no DTCs. No spark from coil tower with spark tester installed and all else hooked up.
Apr 24, 2012 at 9:16 PM
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DOCFIXIT
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Would try another scan tool if same results ,not able to force a code suspect PCM
Apr 26, 2012 at 4:16 PM
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LINDOPARK
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I am considering disconnecting the ICM signal wire from the PCM and putting a quick earth to it to see if the ICM will fire the coil. What do you think?
Apr 27, 2012 at 11:14 PM
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DOCFIXIT
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Not a recomended proceedure you can have ICM tested at Auto Zone
May 1, 2012 at 3:42 PM
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LINDOPARK
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Thanks but no Auto Zone, no Tech 2, no Chevy Dealers in this part of the world.
May 1, 2012 at 6:08 PM
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DOCFIXIT
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Bummer go with grounding make sure signal wire unhooked from PCM. Do you have a DVOM?
May 2, 2012 at 2:58 PM